JP5656784B2 - Polymerizable composition, lithographic printing plate precursor using the same, and lithographic printing method - Google Patents

Description

  The present invention relates to a polymerizable composition and a lithographic printing plate precursor using the same. More particularly, the present invention relates to a polymerizable composition which can be directly made from a digital signal of a computer or the like using various lasers, and is preferably used for a lithographic printing plate precursor capable of direct plate making, a lithographic printing plate precursor using the same, and a lithographic printing method.

In general, a lithographic printing plate comprises an oleophilic image area that receives ink in the printing process and a hydrophilic non-image area that receives dampening water. Lithographic printing utilizes the property that water and oil-based inks repel each other, so that the oleophilic image area of the lithographic printing plate is the ink receiving area, and the hydrophilic non-image area is dampened with the water receiving area (ink non-receiving area). In this method, a difference in ink adhesion is caused on the surface of the lithographic printing plate, and after ink is applied only to the image area, the ink is transferred to a printing medium such as paper and printed.
In order to produce this lithographic printing plate, conventionally, a lithographic printing plate precursor (PS plate) in which an oleophilic photosensitive resin layer (image recording layer) is provided on a hydrophilic support is used. After exposure through a mask such as a film, development with an alkaline developer is performed to leave the image recording layer corresponding to the image area, and dissolve and remove the unnecessary image recording layer corresponding to the non-image area. And obtained a lithographic printing plate.

  Due to recent advances in this field, lithographic printing plates are now available with CTP (computer to plate) technology. That is, a lithographic printing plate can be obtained by scanning and exposing a lithographic printing plate precursor directly using a laser or a laser diode without a lith film, and developing it.

  Along with the above progress, problems related to the lithographic printing plate precursor have been changed to improvements in image formation characteristics, printing characteristics, physical characteristics and the like corresponding to the CTP technology. In addition, due to increasing interest in the global environment, environmental issues related to waste liquids associated with wet processing such as development processing have been highlighted as another issue related to lithographic printing plate precursors.

For the above environmental problems, simplification and no processing of development or plate making are directed. As one simple plate making method, a method called “on-press development” is performed. That is, after the exposure of the lithographic printing plate precursor, conventional development is not performed, but it is mounted on a printing machine as it is, and unnecessary portions of the image recording layer are removed at the initial stage of a normal printing process.
In addition, as a simple development method, a method called “gum development” in which unnecessary portions of the image recording layer are removed with a finisher or gum solution having a pH close to neutral instead of a conventional highly alkaline developer is also performed. ing.

  In the simplification of the plate making operation as described above, a system using a lithographic printing plate precursor and a light source that can be handled in a bright room or under a yellow light is preferable in terms of ease of work. A solid-state laser such as a semiconductor laser or a YAG laser emitting an infrared ray of 1200 nm is used. Further, a UV laser can be used.

As a lithographic printing plate precursor capable of on-machine development, for example, in Patent Documents 1 and 2, a lithographic printing plate having an image recording layer (thermosensitive layer) containing a microcapsule containing a polymerizable compound on a hydrophilic support. The original edition is listed. Patent Document 3 describes a lithographic printing plate precursor in which an image recording layer (photosensitive layer) containing an infrared absorber, a radical polymerization initiator, and a polymerizable compound is provided on a support. Further, in Patent Document 4, on-press development is possible in which an image recording layer containing a polymerizable compound and a graft polymer having a polyethylene oxide chain in the side chain or a block polymer having a polyethylene oxide block is provided on a support. A planographic printing plate precursor is described. Patent Document 5 also discloses a lithographic printing plate precursor provided with an image forming layer containing a polymer compound having a main chain branched into 3 or more on a support as a lithographic printing plate precursor that can be developed on the machine. Proposed.
However, these techniques are still insufficient to obtain both good developability and high printing durability.

JP 2001-277740 A JP 2001-277742 A JP 2002-287334 A US Patent Application Publication No. 2003/0064318 Japanese Patent Laid-Open No. 2007-249036

  An object of the present invention is to provide a polymerizable composition capable of forming a good polymerized cured film without film loss. Another object of the present invention is to provide a lithographic printing plate precursor capable of obtaining good developability while maintaining printing durability when the polymerizable composition is used in an image recording layer of the lithographic printing plate precursor. It is to provide a lithographic printing method.

As a result of intensive studies, the inventor of the present invention has been able to solve the above-described problems by including a polymerizable composition containing a polymer compound having a specific structure in the image recording layer. That is, the present invention is as follows.
<1>
A lithographic printing plate precursor having an image recording layer containing a polymerizable composition on a support,
The polymerizable composition contains a polymerizable compound, a polymerization initiator, and a polymer compound,
A lithographic printing plate precursor, wherein the polymer compound is a polymer compound having an isocyanuric acid skeleton as a branch and a polymer chain branched.
<2>
The lithographic printing plate precursor as described in <1>, wherein the polymer chain contains a repeating unit having an ethylenically unsaturated group.
<3>
The lithographic printing plate precursor as described in <1> or <2>, wherein the polymerizable compound has an isocyanuric acid skeleton.
<4>
The lithographic printing plate precursor as described in any one of <1> to <3>, wherein the image recording layer is removable by at least one of printing ink and fountain solution.
<5>
<4> The lithographic printing plate precursor described in <4> is mounted on a printing press and imagewise exposed with a laser, or after imagewise exposure with a laser, and then mounted on a printing press to form the lithographic printing plate precursor. A lithographic printing method in which at least one of printing ink and fountain solution is supplied to remove an unexposed portion of the image recording layer and print.
Although this invention is invention which concerns on said <1>-<5>, hereafter, it describes also about other matters (for example, the following 1-6).

1. A polymerizable composition comprising a polymerizable compound, a polymerization initiator, and a polymer compound, wherein the polymer compound is a polymer compound in which the polymer chain is branched with the isocyanuric acid skeleton as a branch. A polymerizable composition characterized.
2. 2. The polymerizable composition as described in 1 above, wherein the polymer chain contains a repeating unit having an ethylenically unsaturated group.
3. 3. The polymerizable composition as described in 1 or 2 above, wherein the polymerizable compound has an isocyanuric acid skeleton.
4). A lithographic printing plate precursor having an image recording layer on a support, wherein the image recording layer contains the polymerizable composition described in any one of 1 to 3 above.
5. 5. The lithographic printing plate precursor as described in 4 above, wherein the image recording layer can be removed with at least one of printing ink and fountain solution.
6). The lithographic printing plate precursor as described in 5 above is mounted on a printing press and imagewise exposed with a laser or imagewise exposed with a laser and then mounted on a printing press and printed on the lithographic printing plate precursor A lithographic printing method in which at least one of ink and fountain solution is supplied to remove an unexposed portion of the image recording layer and print.

In the present invention, the use of a polymerizable composition containing a polymer compound having an isocyanuric acid skeleton as a branch and having a polymer chain branched can achieve the solution to the above-described problem.
The mechanism of action is not clear, but the polymer compound has an isocyanuric acid skeleton, thereby forming a strong polymerized cured film that does not lose its thickness, and it is compatible with a polymerizable compound having an isocyanuric acid skeleton. Thus, it is considered that a strong polymerized and cured film is formed in the exposed area without film loss, and is easily removed in the unexposed area during development.

  ADVANTAGE OF THE INVENTION According to this invention, the polymeric composition which can form the favorable polymeric cured film without a film reduction can be provided. Further, by using the polymerizable composition in the image recording layer, a lithographic printing plate precursor having good developability while maintaining printing durability can be provided.

The figure which shows the structure of the automatic developing processor used in the Example.

The present invention will be described in detail below.
(Polymerizable composition)
The polymerizable composition of the present invention contains a polymerizable compound, a polymerization initiator, and a polymer compound in which the polymer chain is branched from the isocyanuric acid skeleton.

[High molecular compound with branched isocyanuric acid skeleton and polymer chain]
The polymer compound having the isocyanuric acid skeleton of the present invention as a branch point and having a branched polymer chain (hereinafter also referred to as “polymer compound of the present invention”) is represented by the following general formula (1). Molecular compounds are particularly preferred.

L _{1 to} L ₃ are each independently a divalent or higher valent linking group having one or more elements selected from C, O, N, halogen, P, Si, S, and H, and particularly preferred is C , A divalent or higher valent linking group having one or more elements selected from O, N, and H. m, n, and k are each independently an integer of 1 or more. Specific examples of L _{1 to} L ₃ used in the present invention are described below, but the present invention is not limited to these.

As long as Polymer in the general formula (1) has a structure in which the isocyanuric acid skeleton is a branch point and the polymer chain is branched, any polymer chain can be suitably used. For example, the acrylic resin and polyvinyl acetal resin which have film property are mentioned.
Especially, it is more preferable that the polymer chain is formed of (a1) a repeating unit having at least one hydrophilic functional group and (a2) a repeating unit having at least one hydrophobic functional group.

To form a polymer chain (a1) a repeating unit having at least one hydrophilic functional ^{_{group, -COOM 1, -SO 3 M 1}} , -OH, -OSO 3 M 1, -CONR 1 R 2, -SO 2 NR 1 ^{_{R 2, -NR 1 SO 3 M}} 1, -P (= O) (OM 1) (O M 2), - OP (= O) (OM 1) (OM 2), - Y 3 N + R 1 R ² L ³¹ A ⁻ , —Y ³ PO ₄ ⁻ L ³² E ⁺ (M ¹ and M ² represent a hydrogen ion, a metal ion, an ammonium ion or a phosphonium ion, and R ¹ and R ² each independently represent a hydrogen atom, An alkyl group, an alkenyl group, an aryl group or a heterocyclic group), a repeating unit having a functional group represented by ethylene oxide or propylene oxide.
R ¹ and R ² may be linked to each other to form a ring structure, L ³¹ represents a linking group, and A ⁻ represents a structure having an anion. Y ³ represents a single bond or a divalent linking group selected from the group consisting of —CO—, —O—, —NH—, a divalent aliphatic group, a divalent aromatic group, and combinations thereof. Represent. L ³² represents a linking group, and E ⁺ represents a structure having a cation. )

When M ¹ and M ² represent metal ions, specific examples of metal ions include Li ⁺ , Na ⁺ , K ⁺ , and Cu ⁺ . Of these, Li ⁺ , Na ⁺ , and K ⁺ are particularly preferable.
When M ¹ and M ² each represent an ammonium ion, any normal ammonium ion can be preferably used, but an ammonium ion having 24 or less carbon atoms per molecule is preferred, and carbon per molecule is preferred. An ammonium ion having a number of 16 or less is particularly preferred.
When M ¹ and M ² represent a phosphonium ion, any ordinary phosphonium ion can be used suitably, but a phosphonium ion having 24 or less carbon atoms per molecule is preferred, and carbon per molecule is preferred. A phosphonium ion having a number of 16 or less is particularly preferred.

When R ¹ and R ² represent an alkyl group, they may be branched or cyclic as long as they are ordinary alkyl groups, and may be a halogen atom, an ether group, a thioether group, a hydroxy group, a cyano group, a keto group, Carboxylic acid group, carboxylic acid group, carboxylic acid ester group, carboxylic acid amide group, sulfonic acid group, sulfonic acid group, sulfonic acid ester group, sulfonamide group, sulfone group, sulfoxide group, phenyl group, phosphonic acid group, phosphonic acid It may have a substituent such as a base, a phosphate group, a phosphate group, an amino group, an aminocarbonyl group, an aminocarboxyl group, and an aminosulfonyl group. Particularly preferred as the alkyl group is an alkyl group having a total carbon number of 12 or less.

When R ¹ and R ² represent an alkenyl group, they may be branched or cyclic as long as they are ordinary alkenyl groups, and may be halogen atoms, ether groups, thioether groups, hydroxy groups, cyano groups, keto groups, Carboxylic acid group, carboxylic acid group, carboxylic acid ester group, carboxylic acid amide group, sulfonic acid group, sulfonic acid group, sulfonic acid ester group, sulfonamide group, sulfone group, sulfoxide group, phenyl group, phosphonic acid group, phosphonic acid It may have a substituent such as a base, a phosphate group, a phosphate group, an amino group, an aminocarbonyl group, an aminocarboxyl group, and an aminosulfonyl group. Particularly preferred as the alkenyl group is an alkenyl group having a total carbon number of 12 or less.

When R ¹ and R ² each represents an aryl group, any normal aryl group can be preferably used. Such aryl groups are halogen atoms, ether groups, thioether groups, hydroxy groups, cyano groups, nitro groups, keto groups, carboxylic acid groups, carboxylic acid groups, carboxylic acid ester groups, carboxylic acid amide groups, sulfonic acid groups, sulfonic acid groups. Base, sulfonic acid ester group, sulfonamide group, sulfone group, sulfoxide group, phenyl group, phosphonic acid group, phosphonic acid group, phosphoric acid group, phosphoric acid group, amino group, aminocarbonyl group, aminocarboxyl group, aminosulfonyl group And the like. Particularly preferred as the aryl group is an aryl group having a total carbon number of 12 or less.

  As long as the repeating unit having (a1) at least one hydrophilic functional group forming the polymer chain is formed from a repeating unit having at least one of these functional groups, any repeating unit can be preferably used. Specific examples of the repeating unit having a hydrophilic functional group used in the present invention are described below. The present invention is not limited to these.

  The (a1) repeating unit having at least one hydrophilic functional group forming the polymer chain may be formed by the repeating unit having the hydrophilic functional group as described above alone or by two or more kinds. .

  The (a2) repeating unit having at least one hydrophobic functional group used in the polymer chain is a repeating unit having no hydrophilic functional group. Specific examples of such repeating units are described below. The present invention is not limited to these.

  (A2) The repeating unit having at least one hydrophobic functional group forming the polymer chain may be formed of a single type of repeating unit having the hydrophobic functional group as described above, or may be formed of two or more types. Also good.

  Any polymer in the general formula (1) used in the present invention can be suitably used as long as it is formed by the repeating units represented by the above (a1) and (a2). (A1) is preferably contained in a proportion of 5 mol% to 60 mol%, more preferably 10 mol% to 50 mol%, and (a2) is preferably contained in a proportion of 40 mol% to 95 mol%, more preferably 50 mol% to 90 mol%.

  As long as the polymer compound used in the present invention has a structure in which the isocyanuric acid skeleton is branched and the polymer chain is branched as described above, any polymer chain can be preferably used, but is branched. It is more desirable that the polymer chain contains a repeating unit having an ethylenically unsaturated group for improving the film strength of the image area. Ethylenically unsaturated groups form crosslinks between polymer molecules to promote curing.

  As the ethylenically unsaturated group, a (meth) acryl group, a vinyl group, an allyl group, a styryl group and the like are preferable, and these groups can be introduced into a polymer by a polymer reaction or copolymerization. For example, a reaction between an acrylic polymer having a carboxy group in the side chain and glycidyl methacrylate, a reaction between a polymer having an epoxy group and an ethylenically unsaturated group-containing carboxylic acid such as methacrylic acid, or a methacrylate having a hydroxy group and an isocyanate group. Reaction can be used.

  Specific examples of the repeating unit having an ethylenically unsaturated group used in the present invention are described below. The present invention is not limited to these.

  The content of the ethylenically unsaturated group in the polymer compound of the present invention is preferably 0.1 to 10.0 mmol, more preferably 0.25 to 7.0 mmol, most preferably 0, per 1 g of the polymer compound. .5 to 5.5 mmol.

Specific examples of the branched polymer (polymer compound of the present invention) used in the present invention are shown below. However, the present invention is not limited to these.
In addition, in the following exemplary compounds, the numerical value written together with the repeating unit (value written together with the main chain repeating unit) represents the mole percentage of the repeating unit.

  One type of the polymer compound of the present invention may be used alone, or two or more types may be mixed and used.

The mass average molar mass (Mw) of the polymer compound of the present invention is preferably 5,000 to 500,000, more preferably 10,000 to 250,000.
The mass average molar mass (Mw) is measured by gel permeation chromatography (GPC) method using tetrahydrofuran as a developing solvent and monodisperse polystyrene as a standard substance.

  For example, when the polymerizable composition of the present invention is used for the image recording layer of a lithographic printing plate precursor, the content of the polymer compound of the present invention is 0.5 to 90 with respect to the total solid content of the image recording layer. The content is preferably mass%, more preferably 1 to 80 mass%, still more preferably 1.5 to 70 mass%.

  The hyperbranched polymer used in the present invention (the polymer compound of the present invention) is a radical functionalized polymer using a polymerization initiator and / or chain transfer agent containing a specific functional group in the molecule, and then a specific functional group. It can be synthesized by a known polymerization method such as a method of condensing with a polyfunctional compound having a large number of functional groups capable of reacting with and a method of radical polymerization using a polyfunctional chain transfer agent. To the radical polymerization using a polyfunctional chain transfer agent is particularly preferred.

(Polymerization initiator)
As a polymerization initiator used for this invention, the compound which starts and accelerates | stimulates superposition | polymerization of a polymeric compound is shown. As the polymerization initiator that can be used in the present invention, a radical polymerization initiator is preferable, and a known thermal polymerization initiator, a compound having a bond with a small bond dissociation energy, a photopolymerization initiator, and the like can be used.
Examples of the polymerization initiator in the present invention include (a) an organic halide, (b) a carbonyl compound, (c) an azo compound, (d) an organic peroxide, (e) a metallocene compound, (f) an azide compound, (G) hexaarylbiimidazole compounds, (h) organic borate compounds, (i) disulfone compounds, (j) oxime ester compounds, (k) onium salt compounds, and the like.

  (A) As the organic halide, compounds described in paragraph numbers [0022] to [0023] of JP-A-2008-195018 are preferable.

  (B) As the carbonyl compound, compounds described in paragraph [0024] of JP-A-2008-195018 are preferable.

  (C) As the azo compound, for example, an azo compound described in JP-A-8-108621 can be used.

  (D) As the organic peroxide, for example, compounds described in paragraph [0025] of JP-A-2008-195018 are preferable.

  As the (e) metallocene compound, for example, the compound described in paragraph [0026] of JP-A-2008-195018 is preferable.

(F) Examples of the azide compound include 2,6-bis (4-azidobenzylidene) -4-methylcyclohexanone.
(G) As the hexaarylbiimidazole compound, for example, a compound described in paragraph [0027] of JP-A-2008-195018 is preferable.

  (H) As the organic borate compound, for example, a compound described in paragraph [0028] of JP-A-2008-195018 is preferable.

  (I) Examples of the disulfone compound include compounds described in JP-A Nos. 61-166544 and 2002-328465.

  (J) As the oxime ester compound, for example, compounds described in paragraph numbers [0028] to [0030] of JP-A-2008-195018 are preferable.

(K) Examples of the onium salt compounds include S.I. I. Schlesinger, Photogr. Sci. Eng. , 18, 387 (1974), T.A. S. Bal et al, Polymer, 21, 423 (1980), diazonium salts described in JP-A-5-158230 (corresponding to NI3 diazonium), US Pat. No. 4,069,055, JP-A-4-365049 Ammonium salts described in U.S. Pat. Nos. 4,069,055 and 4,069,056, EP 104,143, U.S. Patent Application Publication No. 2008/0311520 Nos. 1-150848, JP-A-2-150848, JP-A-2008-195018, or J. Pat. V. Ivonium salt described in Crivello et al, Macromolecules, 10 (6), 1307 (1977), European Patents 370,693, 233,567, 297,443, 297,442, US Patent 4,933,377, 4,760,013, 4,734,444, 2,833,827, German Patent 2,904,626, 3,604,580 Sulphonium salts described in the respective specifications of U.S. Pat. V. Crivello et al, J.A. Polymer Sci. , Polymer
Chem. Ed. , 17, 1047 (1979), a selenonium salt described in C.I. S. Wen et al, Teh, Proc. Conf. Rad. Curing ASIA, p478 Tokyo, Oct (1988), and onium salts such as azinium salts described in JP-A-2008-195018.

  Of these, more preferred are onium salts, especially iodonium salts, sulfonium salts and azinium salts. Although the specific example of these compounds is shown below, it is not limited to this.

  As an example of the iodonium salt, a diphenyl iodonium salt is preferable, and a diphenyl iodonium salt substituted with an electron donating group such as an alkyl group or an alkoxyl group is particularly preferable, and an asymmetric diphenyl iodonium salt is more preferable. Specific examples include diphenyliodonium = hexafluorophosphate, 4-methoxyphenyl-4- (2-methylpropyl) phenyliodonium = hexafluorophosphate, 4- (2-methylpropyl) phenyl-p-tolyliodonium = hexa. Fluorophosphate, 4-hexyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, 4-hexyloxyphenyl-2,4-diethoxyphenyliodonium = tetrafluoroborate, 4-octyloxy Phenyl-2,4,6-trimethoxyphenyliodonium = 1-perfluorobutanesulfonate, 4-octyloxyphenyl-2,4,6-trimethoxyphenyliodonium = hexafluorophosphate, bis ( -t- butylphenyl) iodonium tetraphenylborate and the like.

  Examples of sulfonium salts include triphenylsulfonium = hexafluorophosphate, triphenylsulfonium = benzoylformate, bis (4-chlorophenyl) phenylsulfonium = benzoylformate, bis (4-chlorophenyl) -4-methylphenylsulfonium = Examples thereof include tetrafluoroborate, tris (4-chlorophenyl) sulfonium = 3,5-bis (methoxycarbonyl) benzenesulfonate, and tris (4-chlorophenyl) sulfonium = hexafluorophosphate.

  Examples of azinium salts include 1-cyclohexylmethyloxypyridinium = hexafluorophosphate, 1-cyclohexyloxy-4-phenylpyridinium = hexafluorophosphate, 1-ethoxy-4-phenylpyridinium = hexafluorophosphate, 1-cyclohexyl (2-ethylhexyloxy) -4-phenylpyridinium = hexafluorophosphate, 4-chloro-1-cyclohexylmethyloxypyridinium = hexafluorophosphate, 1-ethoxy-4-cyanopyridinium = hexafluorophosphate, 3,4 -Dichloro-1- (2-ethylhexyloxy) pyridinium = hexafluorophosphate, 1-benzyloxy-4-phenylpyridinium = hexafluorophosphate, 1-phenethylo Ci-4-phenylpyridinium = hexafluorophosphate, 1- (2-ethylhexyloxy) -4-phenylpyridinium = p-toluenesulfonate, 1- (2-ethylhexyloxy) -4-phenylpyridinium = perfluorobutanesulfonate 1- (2-ethylhexyloxy) -4-phenylpyridinium bromide, 1- (2-ethylhexyloxy) -4-phenylpyridinium tetrafluoroborate.

  When the polymerizable composition of the present invention is used for an image recording layer of a lithographic printing plate precursor, the polymerization initiator is preferably 0.1 to 50% by mass, more preferably based on the total solid content constituting the image recording layer. It can be added in a proportion of 0.5 to 30% by mass, particularly preferably 0.8 to 20% by mass. Within this range, good sensitivity and good stain resistance of the non-image area during printing can be obtained.

[Polymerizable compound]
The polymerizable compound used in the polymerizable composition in the present invention is an addition polymerizable compound having at least one ethylenically unsaturated double bond, and has at least one terminal ethylenically unsaturated bond, preferably two or more. Selected from compounds. These have chemical forms such as monomers, prepolymers, ie dimers, trimers and oligomers, or mixtures thereof.

  Examples of monomers include unsaturated carboxylic acids (for example, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, etc.), esters and amides thereof, preferably unsaturated carboxylic acids. An ester of an acid and a polyhydric alcohol compound and an amide of an unsaturated carboxylic acid and a polyvalent amine compound are used. In addition, an addition reaction product of an unsaturated carboxylic acid ester or amide having a nucleophilic substituent such as a hydroxy group, an amino group or a mercapto group with a monofunctional or polyfunctional isocyanate or epoxy, and a monofunctional or polyfunctional compound. A dehydration condensation reaction product with a functional carboxylic acid is also preferably used. Further, an addition reaction product of an unsaturated carboxylic acid ester or amide having an electrophilic substituent such as an epoxy group or an epoxy group with a monofunctional or polyfunctional alcohol, amine or thiol, a halogen group or In addition, a substitution reaction product of an unsaturated carboxylic acid ester or amide having a leaving substituent such as a tosyloxy group and a monofunctional or polyfunctional alcohol, amine or thiol is also suitable. As another example, it is also possible to use a group of compounds substituted with unsaturated phosphonic acid, styrene, vinyl ether or the like instead of the unsaturated carboxylic acid. These are disclosed in JP-T-2006-508380, JP-A-2002-287344, JP-A-2008-256850, JP-A-2001-342222, JP-A-9-179296, JP-A-9-179297. JP-A-9-179298, JP-A-2004-294935, JP-A-2006-243493, JP-A-2002-275129, JP-A-2003-64130, JP-A-2003-280187, It is described in references including Kaihei 10-333321.

  Specific examples of the monomer of the ester of a polyhydric alcohol compound and an unsaturated carboxylic acid include acrylic acid esters such as ethylene glycol diacrylate, 1,3-butanediol diacrylate, tetramethylene glycol diacrylate, propylene glycol diacrylate, Examples include trimethylolpropane triacrylate, hexanediol diacrylate, tetraethylene glycol diacrylate, pentaerythritol tetraacrylate, sorbitol triacrylate, isocyanuric acid ethylene oxide (EO) -modified triacrylate, and polyester acrylate oligomer. Methacrylic acid esters include tetramethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, pentaerythritol trimethacrylate, bis [p- (3-methacryloxy-2-hydroxypropoxy) phenyl ] Dimethylmethane, bis- [p- (methacryloxyethoxy) phenyl] dimethylmethane, and the like. Specific examples of amide monomers of polyvalent amine compounds and unsaturated carboxylic acids include methylene bis-acrylamide, methylene bis-methacrylamide, 1,6-hexamethylene bis-acrylamide, 1,6-hexamethylene bis-methacrylic. Examples include amide, diethylenetriamine trisacrylamide, xylylene bisacrylamide, and xylylene bismethacrylamide.

In addition, urethane-based addition-polymerizable compounds produced by using an addition reaction between an isocyanate and a hydroxy group are also suitable, and specific examples thereof include, for example, one molecule described in Japanese Patent Publication No. 48-41708. A vinyl containing two or more polymerizable vinyl groups in one molecule obtained by adding a vinyl monomer containing a hydroxy group represented by the following general formula (A) to a polyisocyanate compound having two or more isocyanate groups. A urethane compound etc. are mentioned.
^{_{CH 2 = C (R 4)}} COOCH 2 CH (R 5) OH (A)
(However, R ⁴ and R ⁵ represent H or CH _3. )

  Also, urethanes described in JP-A-51-37193, JP-B-2-32293, JP-B-2-16765, JP-A-2003-344997, and JP-A-2006-65210. Acrylates, JP-B 58-49860, JP-B 56-17654, JP-B 62-39417, JP-B 62-39418, JP-A 2000-250211, JP-A 2007-94138 Urethane compounds having an ethylene oxide skeleton described in the publication, and hydrophilic groups described in US Pat. No. 7,153,632, JP-A-8-505958, JP-A-2007-293221, and JP-A-2007-293223. Also suitable are urethane compounds having.

  Among the above, polymerization having an isocyanuric acid skeleton represented by the following general formula (2) is particularly preferable from the viewpoint of excellent balance between the hydrophilicity involved in on-press developability and the polymerization ability involved in printing durability. It is a sex compound.

In General Formula (2), L _{1 to} L ₃ are a single bond or a linking group having the same meaning as in General Formula (1) L ₁ -L ₃ . R _{1 to} R ₃ each independently represents a hydrogen atom or a group selected from an alkyl group, an aryl group, and a heterocyclic group, and at least one of R _{1 to} R ₃ has an ethylenically unsaturated group. As the ethylenically unsaturated group, a (meth) acryl group, a vinyl group, an allyl group, a vinylphenyl group and the like are preferable.

Examples of the alkyl group represented by R _{1 to} R ₃ include linear, branched or cyclic alkyl groups having 1 to 20 carbon atoms. Among these, a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms, and a cyclic alkyl group having 5 to 10 carbon atoms are more preferable.
Specific examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, hexadecyl, Octadecyl group, eicosyl group, isopropyl group, isobutyl group, s-butyl group, t-butyl group, isopentyl group, neopentyl group, 1-methylbutyl group, isohexyl group, 2-ethylhexyl group, 2-methylhexyl group, cyclohexyl group, Examples thereof include a cyclopentyl group and a 2-norbornyl group, and it is preferable that a hydroxy group is further contained.

The aryl group represented by R _{1 to} R ₃ is preferably a benzene ring having 6 to 30 carbon atoms, a benzene ring having 2 to 5 benzene rings forming a condensed ring, a benzene ring and a 5-7 member. Examples include those in which an unsaturated ring forms a condensed ring. Among these, a benzene ring and a naphthalene ring are more preferable. Moreover, the aryl group represented by R _{1 to} R ₃ may have a substituent on the carbon atom forming the ring. As such a substituent, the aforementioned R _{1 to} R ₃ are alkyl. The example of a substituent when expressing a group can be mentioned as a preferable thing.
When the aryl group represented by R _{1 to} R ₃ has a substituent, the aryl group includes a halogen atom, an ether group, a thioether group, a hydroxy group, a cyano group, a nitro group, a keto group, a carboxylic acid group, and a carboxylic acid. Base, carboxylic acid ester group, carboxylic acid amide group, sulfonic acid group, sulfonic acid group, sulfonic acid ester group, sulfonamide group, sulfone group, sulfoxide group, phenyl group, phosphonic acid group, phosphonic acid group, phosphoric acid group, It may have a substituent such as phosphate group, amino group, aminocarbonyl group, aminocarboxyl group, aminosulfonyl group. Particularly preferred as the aryl group is an aryl group having a total carbon number of 12 or less.

As the heterocyclic group represented by R _{1 to} R ₃ , an optionally condensed 3-membered to 8-membered heterocyclic group having 6 to 30 carbon atoms is preferable, and a nitrogen atom, oxygen A 3- to 6-membered heterocyclic group containing an atom or a sulfur atom is more preferred, and a 5- or 6-membered heterocyclic group containing a nitrogen atom, an oxygen atom or a sulfur atom is more preferred. Specifically, pyrrole ring group, furan ring group, thiophene ring group, benzopyrrole ring group, benzofuran ring group, benzothiophene ring group, pyrazole ring group, isoxazole ring group, isothiazole ring group, indazole ring group, benzoiso Xazole ring group, benzoisothiazole ring group, imidazole ring group, oxazole ring group, thiazole ring group, benzimidazole ring group, benzoxazole ring group, benzothiazole ring group, pyridine ring group, quinoline ring group, isoquinoline ring group, Pyridazine ring group, pyrimidine ring group, pyrazine ring group, phthalazine ring group, quinazoline ring group, quinoxaline ring group, acylidin ring group, phenanthridine ring group, carbazole ring group, purine ring group, pyran ring group, piperidine ring group, Piperazine ring group, morpholine ring group, indole ring group, indolizine ring group, Road ring group, a cinnoline ring group, an acridine ring group, a phenothiazine ring group, a tetrazole ring group, a triazine ring group, and the like.

In addition, the heterocyclic group represented by R _{1 to} R ₃ may have a substituent on the carbon atom forming the ring, and examples of such a substituent include the aforementioned R _{1 to} R _3. The example of a substituent when representing an alkyl group can be mentioned as a preferable example.

Of the groups represented by R _{1 to} R ₃ , an alkyl group further having a hydroxy group is particularly preferable. Further, the groups represented by R _{1 to} R ₃ may be separate groups, or two or more may be the same group, but R _{1 to} R ₃ are all the same group. It is more preferable.

Specific examples of particularly preferable groups represented by R _{1 to} R ₃ will be given below, but are not limited thereto.
N- (2-hydroxyethyl) carbamoylethyl group, N- (3-hydroxypropyl) carbamoylethyl group, N- (2-hydroxyethyl) carbamoylpropyl group, N- (3-hydroxypropyl) carbamoylpropyl group, N- (2- (2-hydroxyethoxy) ethyl) carbamoylethyl group, N, N-di (2-hydroxyethyl) carbamoylethyl group, N, N-di (2- (2-hydroxyethoxy) ethyl) carbamoylethyl group, N- (2-hydroxyethyl) carbamoyloxyethyl group, N- (3-hydroxypropyl) carbamoyloxyethyl group, N- (2- (2-hydroxyethoxy) ethyl) carbamoyloxyethyl group, N- (2- ( 2- (2-hydroxyethoxy) ethoxy) ethyl) carbamoyloxy Til group, 2- (N- (2-hydroxyethyl) carbamoyloxy) ethoxyethyl group, 2- (N- (3-hydroxypropyl) carbamoyloxy) ethoxyethyl group, 2- (N- (2- (2- (2- Hydroxyethoxy) ethyl) carbamoyloxy) ethoxyethyl group, 2- (N- (2- (2- (2-hydroxyethoxy) ethoxy) ethyl) carbamoyloxy) ethoxyethyl group, N, N-di (2-hydroxymethyl) ) Carbamoyloxyethyl group, N, N-di (2-hydroxyethyl) carbamoyloxyethyl group, N, N-di (2-hydroxypropyl) carbamoyloxyethyl group, N, N-di (2- (2-hydroxy Ethoxy) ethyl) carbamoyloxyethyl group, N- (2-hydroxyethyl) ureidoethyl group, N- ( -Hydroxypropyl) ureidoethyl group, N- (2- (2-hydroxyethoxy) ethyl) ureidoethyl group, N- (2- (2- (2-hydroxyethoxy) ethoxy) ethyl) ureidoethyl group, 2- ( N- (2-hydroxyethyl) ureido) ethoxyethyl group, 2- (N- (3-hydroxypropyl) ureido) ethoxyethyl group, 2- (N- (2- (2-hydroxyethoxy) ethyl) ureido) ethoxy Ethyl group, 2- (N- (2- (2- (2-hydroxyethoxy) ethoxy) ethyl) ureido) ethoxyethyl group, N, N-di (2-hydroxymethyl) ureidoethyl group, N, N-di (2-hydroxyethyl) ureidoethyl group, N, N-di (2-hydroxypropyl) ureidoethyl group, N, N-di (2- (2-hydroxy) Ciethoxy) ethyl) ureidoethyl group, 3- (N- (hydroxymethylcarbonyl) amino) propyl group, 2-hydroxy-3- (N- (hydroxymethylcarbonyl) amino) propyl group, 3- (N-((2 -Hydroxyethoxy) methylcarbonyl) amino) propyl group, N- (2-hydroxyethyl) carbamoyloxypropyl group, N- (1,2-dihydroxyethyl) carbamoyloxypropyl group, 2-hydroxy-3- (N- ( 1,2-dihydroxyethyl) carbamoyloxy) propyl group, N- (2-hydroxyethoxycarbonyl) aminoethyl group, N- (2-hydroxyethoxycarbonyl) aminopropyl group, N- (3-hydroxypropoxycarbonyl) aminoethyl Group, N- (3-hydroxypropoxyl Nyl) aminopropyl group, N- (2,3-dihydroxypropoxycarbonyl) aminoethyl group, N- (2,3-dihydroxypropoxycarbonyl) aminopropyl group, N- (2-hydroxyethyl) ureidopropyl group, N- (1,2-dihydroxyethyl) ureidoethyl group, N- (1,2-dihydroxyethyl) ureidopropyl group.

  Specific examples of the polymerizable compound used in the present invention are described below. The present invention is not limited to these.

  Details of the method of use such as the structure of these polymerizable compounds, single use or combination, addition amount, etc. can be arbitrarily set in accordance with the final polymerizable composition or the performance design of the following lithographic printing plate precursor . When the polymerizable composition of the present invention is used for the image recording layer of a lithographic printing plate precursor, the polymerizable compound is preferably 1 to 75% by mass, more preferably 3%, based on the total solid content of the image recording layer. It is used in a range of ˜70% by mass, particularly preferably 5 to 60% by mass.

[Lithographic printing plate precursor]
The lithographic printing plate precursor according to the invention has an image recording layer containing the polymerizable composition on a surface hydrophilic support. If necessary, an undercoat layer can be provided between the support and the image recording layer, and a protective layer can be provided on the image recording layer.

(Image recording layer)
The image recording layer of the present invention contains the polymerizable composition. Hereinafter, the constituent components of the image recording layer other than the polymerizable composition will be described in detail.
The image recording layer used in the present invention is preferably an image recording layer that can be developed on-press. The image recording layer may contain a sensitizing dye, and when it contains an infrared absorbing dye as the sensitizing dye, it may further contain a hydrophobizing precursor. A hydrophobic region (image part) is formed by using heat fusion and thermal reaction of the hydrophobized precursor together.

[Sensitizing dye]
The sensitizing dye is particularly limited as long as it absorbs light at the time of image exposure to be in an excited state and supplies energy to the polymerization initiator by electron transfer, energy transfer or heat generation to improve the polymerization initiation function. It can be used without. In particular, a sensitizing dye having a maximum absorption in a wavelength region of 350 to 450 nm or 750 to 1400 nm is preferably used.

  Examples of the sensitizing dye having the maximum absorption in the wavelength range of 350 to 450 nm include merocyanine dyes, benzopyrans, coumarins, aromatic ketones, and anthracenes.

  Of the sensitizing dyes having the maximum absorption in the wavelength range of 350 nm to 450 nm, a more preferable dye from the viewpoint of high sensitivity is a dye represented by the following general formula (I).

(In General Formula (I), A represents an aromatic ring group or a heterocyclic group which may have a substituent, and X represents an oxygen atom, a sulfur atom, or N- (R ₃ ). R ₁ , R ₂ and R ₃ each independently represent a monovalent nonmetallic atomic group, and A and R ₁ or R ₂ and R ₃ are bonded to each other to form an aliphatic or aromatic ring. May be good.)

The general formula (I) will be described in more detail. R ₁ , R ₂ and R ₃ are each independently a monovalent nonmetallic atomic group, preferably a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group Represents a substituted or unsubstituted aromatic heterocyclic residue, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted alkylthio group, a hydroxy group, or a halogen atom.

Next, A in the general formula (I) will be described. A represents an aromatic ring group or a heterocyclic group which may have a substituent. Specific examples of the aromatic ring or heterocyclic ring which may have a substituent include R ₁ in the general formula (I). , R ₂ and R ₃ are the same as the substituted or unsubstituted aryl group and the substituted or unsubstituted aromatic heterocyclic residue.

  Specific examples of such sensitizing dyes include compounds described in paragraphs [0047] to [0053] of JP-A-2007-58170.

  Furthermore, sensitizing dyes represented by the following general formula (II) or (III) can also be used.

In formula (II), R ^{1 to} R ¹⁴ each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{1 to} R ¹⁰ represents an alkoxy group having 2 or more carbon atoms.
In formula (III), R ^{15 to} R ³² each independently represents a hydrogen atom, an alkyl group, an alkoxy group, a cyano group, or a halogen atom. However, at least one of R ^{15 to} R ²⁴ represents an alkoxy group having 2 or more carbon atoms.

  As specific examples of such sensitizing dyes, compounds described in European Patent Application Publication No. 1349006 and International Publication No. 2005/029187 are preferably used.

  JP 2007-171406, JP 2007-206216, JP 2007-206217, JP 2007-225701, JP 2007-225702, JP 2007-316582, JP 2007-328243. The sensitizing dyes described in each of the above publications can also be preferably used.

  Subsequently, a sensitizing dye having a maximum absorption in the wavelength range of 750 to 1400 nm that is preferably used in the present invention (hereinafter sometimes referred to as “infrared absorber”) will be described in detail. As the infrared absorber, a dye or a pigment is preferably used.

As the dye, commercially available dyes and known dyes described in documents such as “Dye Handbook” (edited by the Society for Synthetic Organic Chemistry, published in 1970) can be used. Specifically, dyes such as azo dyes, metal complex azo dyes, pyrazolone azo dyes, naphthoquinone dyes, anthraquinone dyes, phthalocyanine dyes, carbonium dyes, quinoneimine dyes, methine dyes, cyanine dyes, squarylium dyes, pyrylium salts, metal thiolate complexes, etc. Is mentioned.
Particularly preferred among these dyes are cyanine dyes, squarylium dyes, pyrylium salts, nickel thiolate complexes, and indolenine cyanine dyes. Further, cyanine dyes and indolenine cyanine dyes are preferred, and particularly preferred examples include cyanine dyes represented by the following general formula (a).

In general formula (a), X ¹ represents a hydrogen atom, a halogen atom, —NPh ₂ , X ² -L ¹ or a group shown below. Here, X ² represents an oxygen atom, a nitrogen atom, or a sulfur atom, and L ¹ represents an aromatic having a hydrocarbon group having 1 to 12 carbon atoms and a hetero atom (N, S, O, halogen atom, Se). A hydrocarbon group having 1 to 12 carbon atoms including a hetero ring and a group ring is shown. X _a ^- is Z _a which will be described below ^- has the same definition as, R ^a represents a hydrogen atom, an alkyl group, an aryl group, a substituted or unsubstituted amino group, substituted or unsubstituted amino group and a halogen atom.

R ¹ and R ² each independently represent a hydrocarbon group having 1 to 12 carbon atoms. In view of storage stability of the image recording layer coating solution, R ¹ and R ² are preferably hydrocarbon groups having 2 or more carbon atoms. R ¹ and R ² may be bonded to each other to form a ring, and when forming a ring, it is particularly preferable that a 5-membered ring or a 6-membered ring is formed.

Ar ¹ and Ar ² may be the same or different and each represents an aromatic hydrocarbon group which may have a substituent. Preferred aromatic hydrocarbon groups include a benzene ring and a naphthalene ring. Moreover, as a preferable substituent, a C12 or less hydrocarbon group, a halogen atom, and a C12 or less alkoxy group are mentioned. Y ¹ and Y ² may be the same or different and each represents a sulfur atom or a dialkylmethylene group having 12 or less carbon atoms. R ³ and R ⁴ may be the same or different and each represents a hydrocarbon group having 20 or less carbon atoms which may have a substituent. Preferred substituents include alkoxy groups having 12 or less carbon atoms, carboxy groups, and sulfo groups. R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different and each represents a hydrogen atom or a hydrocarbon group having 12 or less carbon atoms. From the availability of raw materials, a hydrogen atom is preferred. Za ⁻ represents a counter anion. However, Za ⁻ is not necessary when the cyanine dye represented by formula (a) has an anionic substituent in its structure and neutralization of charge is not necessary. Preferred Za ⁻ is a halide ion, a perchlorate ion, a tetrafluoroborate ion, a hexafluorophosphate ion, and a sulfonate ion, particularly preferably a perchlorate ion, in view of the storage stability of the image recording layer coating solution. , Hexafluorophosphate ions, and aryl sulfonate ions.

  Specific examples of the cyanine dye represented by the general formula (a) that can be suitably used include those described in paragraph numbers [0017] to [0019] of JP-A No. 2001-133969.

  Further, other particularly preferable examples include specific indolenine cyanine dyes described in JP-A-2002-278057.

  Examples of pigments include commercially available pigment and color index (CI) manuals, “Latest Pigment Handbook” (edited by the Japan Pigment Technology Association, published in 1977), “Latest Pigment Applied Technology” (published by CMC, published in 1986), “Printing” The pigments described in "Ink Technology", published by CMC Publishing, 1984) can be used.

  The preferred addition amount of these sensitizing dyes is preferably 0.05 to 30 parts by mass, more preferably 0.1 to 20 parts by mass, and most preferably 0.2 to 100 parts by mass of the total solid content of the image recording layer. It is the range of -10 mass parts.

  Moreover, only 1 type may be used for these infrared absorption dyes, and 2 or more types may be used together, and infrared absorbers other than infrared absorption dyes, such as a pigment, may be used together. As the pigment, compounds described in paragraph numbers [0072] to [0076] of JP-A-2008-195018 are preferable.

  The content of the infrared absorbing dye in the image recording layer in the present invention is preferably 0.1 to 10.0% by mass, more preferably 0.5 to 5.0% by mass of the total solid content of the image recording layer.

[Hydrophobicized precursor]
In the present invention, a hydrophobized precursor can be used to improve on-press developability. The hydrophobized precursor in the present invention means fine particles capable of converting the image recording layer to hydrophobic when heat is applied. The fine particles are at least one selected from hydrophobic thermoplastic polymer fine particles, thermally reactive polymer fine particles, polymer fine particles having a polymerizable group, microcapsules enclosing a hydrophobic compound, and microgel (crosslinked polymer fine particles). It is preferable. Among these, polymer fine particles and microgels having a polymerizable group are preferable.

Hydrophobic thermoplastic polymer fine particles include Research Disclosure No. 1 of January 1992. 331,003, JP-A-9-123387, JP-A-9-131850, JP-A-9-171249, JP-A-9-171250 and European Patent No. 931647 are suitable. Can be cited as
Specific examples of polymers constituting such polymer fine particles include ethylene, styrene, vinyl chloride, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, vinylidene chloride, acrylonitrile, vinyl carbazole, and polyalkylene structures. Mention may be made of homopolymers or copolymers of monomers such as acrylates or methacrylates or mixtures thereof. Among them, more preferable examples include a copolymer containing polystyrene, styrene and acrylonitrile, and polymethyl methacrylate.

  The average particle diameter of the hydrophobic thermoplastic polymer fine particles used in the present invention is preferably 0.01 to 2.0 μm.

  Examples of the heat-reactive polymer fine particles used in the present invention include polymer fine particles having a heat-reactive group, and these form a hydrophobized region by cross-linking by a heat reaction and a functional group change at that time.

  The thermoreactive group in the polymer fine particles having a thermoreactive group used in the present invention may be any functional group that performs any reaction as long as a chemical bond is formed, but is preferably a polymerizable group, Examples include ethylenically unsaturated groups that undergo radical polymerization reactions (eg, acryloyl groups, methacryloyl groups, vinyl groups, allyl groups, etc.), cationic polymerizable groups (eg, vinyl groups, vinyloxy groups, epoxy groups, oxetanyl groups, etc.) ), An isocyanato group that performs an addition reaction or a block thereof, an epoxy group, a vinyloxy group, and a functional group having an active hydrogen atom that is a reaction partner thereof (for example, an amino group, a hydroxy group, a carboxy group, etc.), and a condensation reaction Carboxy group and reaction partner hydroxy group or amino group, acid anhydride and reaction phase for ring-opening addition reaction , And the like as a preferable amino group or a hydroxy group is.

  As the microcapsules used in the present invention, for example, as described in JP-A Nos. 2001-277740 and 2001-277742, all or part of the constituent components of the image recording layer are encapsulated in the microcapsules. Is. The constituent components of the image recording layer can also be contained outside the microcapsules. Furthermore, it is preferable that the image recording layer containing the microcapsule includes a hydrophobic constituent component in the microcapsule and a hydrophilic constituent component outside the microcapsule.

  In this invention, the aspect containing a crosslinked resin particle, ie, a microgel, may be sufficient. This microgel can contain a part of the constituent components of the image recording layer in at least one of the inside and the surface thereof, and in particular, an embodiment in which a reactive microgel is formed by having a radical polymerizable group on the surface thereof, This is particularly preferable from the viewpoint of image formation sensitivity and printing durability.

  As a method for microencapsulating or microgelling the constituent components of the image recording layer, known methods can be applied.

  The average particle size of the microcapsules or microgel is preferably 0.01 to 3.0 μm. 0.05-2.0 micrometers is still more preferable, and 0.10-1.0 micrometer is especially preferable. Within this range, good resolution and stability over time can be obtained.

  The content of the hydrophobizing precursor is preferably in the range of 5 to 90% by mass of the total solid content of the image recording layer.

(G) Other components The image recording layer in the invention may further contain other components as required.

[Low molecular hydrophilic compounds]
The image recording layer in the invention may contain a low molecular weight hydrophilic compound in order to improve the on-press developability without reducing the printing durability.
As the low molecular weight hydrophilic compound, for example, as the water-soluble organic compound, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol and the like glycols and ether or ester derivatives thereof, glycerin, Polyols such as pentaerythritol and tris (2-hydroxyethyl) isocyanurate, organic amines such as triethanolamine, diethanolamine and monoethanolamine and salts thereof, organic sulfones such as alkylsulfonic acid, toluenesulfonic acid and benzenesulfonic acid Acids and salts thereof, organic sulfamic acids such as alkylsulfamic acid and salts thereof, organic sulfuric acids such as alkylsulfuric acid and alkylethersulfuric acid and salts thereof, phenylphosphonic acid Organic phosphonic acids and salts thereof, tartaric acid, oxalic acid, citric acid, malic acid, lactic acid, gluconic acid, organic carboxylic acids and salts thereof such as amino acids, betaines, and the like.

  Among these, in the present invention, it is preferable to contain at least one selected from the group consisting of polyols, organic sulfates, organic sulfonates, and betaines.

  Specific examples of organic sulfonates include alkyl sulfonates such as sodium n-butyl sulfonate, sodium n-hexyl sulfonate, sodium 2-ethylhexyl sulfonate, sodium cyclohexyl sulfonate, and sodium n-octyl sulfonate. Sodium 5,8,11-trioxapentadecane-1-sulfonate, sodium 5,8,11-trioxaheptadecane-1-sulfonate, 13-ethyl-5,8,11-trioxaheptadecane-1; Alkyl sulfonates containing ethylene oxide chains such as sodium sulfonate, sodium 5,8,11,14-tetraoxatetracosane-1-sulfonate; sodium benzenesulfonate, sodium p-toluenesulfonate, p-hydroxybenzene Sulfone Sodium, sodium p-styrenesulfonate, sodium dimethyl-5-sulfonate isophthalate, sodium 1-naphthylsulfonate, sodium 4-hydroxynaphthylsulfonate, disodium 1,5-naphthalenedisulfonate, 1,3,6- Aryl sulfonates such as trisodium naphthalene trisulfonate, compounds described in paragraph numbers [0026] to [0031] of JP 2007-276454 A and paragraph numbers [0020] to [0047] of JP 2009-154525 A Etc. The salt may be a potassium salt or a lithium salt.

  Organic sulfates include sulfates of alkyl, alkenyl, alkynyl, aryl or heterocyclic monoethers of polyethylene oxide. The number of ethylene oxide units is preferably 1 to 4, and the salt is preferably a sodium salt, potassium salt or lithium salt. Specific examples thereof include the compounds described in paragraph numbers [0034] to [0038] of JP-A-2007-276454.

  As the betaines, compounds having 1 to 5 carbon atoms of the hydrocarbon substituent on the nitrogen atom are preferable. Specific examples include trimethylammonium acetate, dimethylpropylammonium acetate, 3-hydroxy-4-trimethyl. Ammonioobylate, 4- (1-pyridinio) butyrate, 1-hydroxyethyl-1-imidazolioacetate, trimethylammonium methanesulfonate, dimethylpropylammonium methanesulfonate, 3-trimethylammonio-1-propanesulfonate, Examples include 3- (1-pyridinio) -1-propanesulfonate.

  The above low molecular weight hydrophilic compound has a small hydrophobic part structure and almost no surface-active action, so that dampening water penetrates into the exposed part of the image recording layer (image part) and the hydrophobicity and film strength of the image part. Ink acceptability and printing durability of the image recording layer can be maintained satisfactorily.

The amount of these low molecular weight hydrophilic compounds added to the image recording layer is preferably 0.5% by mass or more and 20% by mass or less of the total solid content of the image recording layer. More preferably, they are 1 mass% or more and 15 mass% or less, More preferably, they are 2 mass% or more and 10 mass% or less. In this range, good on-press developability and printing durability can be obtained.
These compounds may be used alone or in combination of two or more.

[Fat Sensitizer]
In the image recording layer of the present invention, a sensitizing agent such as a phosphonium compound, a nitrogen-containing low molecular weight compound, or an ammonium group-containing polymer can be used in the image recording layer in order to improve the inking property. In particular, when an inorganic layered compound is contained in the protective layer, which will be described later, these compounds function as a surface coating agent for the inorganic layered compound and prevent a decrease in the inking property during printing by the inorganic layered compound.

  Suitable phosphonium compounds include phosphonium compounds described in JP-A-2006-297907 and JP-A-2007-50660. Specific examples include tetrabutylphosphonium iodide, butyltriphenylphosphonium bromide, tetraphenylphosphonium bromide, 1,4-bis (triphenylphosphonio) butanedi (hexafluorophosphate), 1,7-bis (tri Phenylphosphonio) heptane sulfate, 1,9-bis (triphenylphosphonio) nonane = naphthalene-2,7-disulfonate, and the like.

  Examples of the nitrogen-containing low molecular weight compound include amine salts and quaternary ammonium salts. Also included are imidazolinium salts, benzoimidazolinium salts, pyridinium salts, and quinolinium salts. Of these, quaternary ammonium salts and pyridinium salts are preferable. Specific examples include tetramethylammonium = hexafluorophosphate, tetrabutylammonium = hexafluorophosphate, dodecyltrimethylammonium = p-toluenesulfonate, benzyltriethylammonium = hexafluorophosphate, benzyldimethyloctylammonium = hexafluorophosphate. Fert, benzyldimethyldodecyl ammonium = hexafluorophosphate, compounds described in paragraph numbers [0021] to [0037] of JP-A-2008-284858, paragraph numbers [0030] to [0057] of JP-A-2009-90645, etc. Is mentioned.

  The ammonium group-containing polymer may be any polymer as long as it has an ammonium group in its structure, but a polymer containing 5 to 80 mol% of a (meth) acrylate having an ammonium group in the side chain as a copolymerization component is preferable. . Specific examples include polymers described in paragraph numbers [0089] to [0105] of JP2009-208458A.

  The ammonium salt-containing polymer has a reduced specific viscosity (unit: ml / g) determined by the following measurement method, preferably in the range of 5 to 120, more preferably in the range of 10 to 110, 15 Those in the range of ~ 100 are particularly preferred. When the said reduced specific viscosity is converted into a mass mean molar mass (Mw), 10,000-150,000 are preferable, 17000-140000 are more preferable, 20000-130000 are especially preferable.

<Measurement method of reduced specific viscosity>
Weigh 3.33 g of 30% polymer solution (1 g as solid content) into a 20 ml volumetric flask and make up with N-methylpyrrolidone. This solution is allowed to stand for 30 minutes in a thermostatic bath at 30 ° C., put in an Ubbelohde reduced specific viscosity tube (viscosity constant = 0.010 cSt / s), and the time for flowing down at 30 ° C. is measured. The measurement is performed twice with the same sample, and the average value is calculated. Similarly, in the case of a blank (only N-methylpyrrolidone), the reduced specific viscosity (ml / g) was calculated from the following formula.

Specific examples of the ammonium group-containing polymer are shown below.
(1) 2- (Trimethylammonio) ethyl methacrylate = p-toluenesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 10/90 Mw 45,000)
(2) 2- (Trimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 60,000)
(3) 2- (Ethyldimethylammonio) ethyl methacrylate = p-toluenesulfonate / hexyl methacrylate copolymer (molar ratio 30/70 Mw 45,000)
(4) 2- (Trimethylammonio) ethyl methacrylate = hexafluorophosphate / 2-ethylhexyl methacrylate copolymer (molar ratio 20/80 Mw 60,000)
(5) 2- (Trimethylammonio) ethyl methacrylate = methyl sulfate / hexyl methacrylate copolymer (molar ratio 40/60 Mw 7 million)
(6) 2- (Butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 25/75 Mw 650,000)
(7) 2- (Butyldimethylammonio) ethyl acrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 65,000)
(8) 2- (butyldimethylammonio) ethyl methacrylate = 13-ethyl-5,8,11-trioxa-1-heptadecanesulfonate / 3,6-dioxaheptyl methacrylate copolymer (molar ratio 20/80 Mw 75,000)
(9) 2- (butyldimethylammonio) ethyl methacrylate = hexafluorophosphate / 3,6-dioxaheptyl methacrylate / 2-hydroxy-3-methacryloyloxypropyl methacrylate copolymer (molar ratio 15/80/5 (Mw 650,000)

  The content of the sensitizer is preferably 0.01 to 30.0% by mass, more preferably 0.1 to 15.0% by mass, and more preferably 1 to 10% by mass with respect to the total solid content of the image recording layer. Is more preferable.

(3) Others Further, as other components, surfactants, colorants, baking-out agents, polymerization inhibitors, higher fatty acid derivatives, plasticizers, inorganic fine particles, inorganic layered compounds, co-sensitizers or chain transfer agents, etc. Can be added. Specifically, paragraph numbers [0114] to [0159] of Japanese Patent Application Laid-Open No. 2008-284817, paragraph numbers [0023] to [0027] of Japanese Patent Application Laid-Open No. 2006-091479, and US Patent Publication No. 2008/0311520. The compounds and addition amounts described in paragraph [0060] are preferred.

(H) Formation of Image Recording Layer The image recording layer in the present invention is prepared by using the above-mentioned necessary components as known solvents as described in, for example, paragraph numbers [0142] to [0143] of JP-A-2008-195018. A coating solution is prepared by dispersing or dissolving in a coating solution, which is formed by applying the coating solution on a support by a known method such as bar coater coating and drying. The image recording layer coating amount (solid content) on the support obtained after coating and drying varies depending on the application, but is generally preferably 0.3 to 3.0 g / m ² . Within this range, good sensitivity and good film characteristics of the image recording layer can be obtained.

(Undercoat layer)
In the lithographic printing plate precursor according to the invention, an undercoat layer (sometimes referred to as an intermediate layer) is preferably provided between the image recording layer and the support. The undercoat layer enhances the adhesion between the support and the image recording layer in the exposed area, and easily peels off the image recording layer from the support in the unexposed area. Contributes to improvement. In the case of infrared laser exposure, the undercoat layer functions as a heat insulating layer, thereby preventing the heat generated by the exposure from diffusing to the support and reducing the sensitivity.

  As the compound used for the undercoat layer, those having an adsorptive group capable of being adsorbed on the surface of the support and a crosslinkable group for improving the adhesion to the image recording layer are preferable. Furthermore, compounds having a hydrophilicity-imparting group such as a sulfo group can also be mentioned as suitable compounds. These compounds may be low molecular weight or high molecular weight polymers. Moreover, you may use these compounds in mixture of 2 or more types as needed.

In the case of a high molecular polymer, a copolymer of a monomer having an adsorptive group, a monomer having a hydrophilic group, and a monomer having a crosslinkable group is preferable. The adsorbable adsorptive group to the surface of the support, a phenolic hydroxy group, a carboxy _{group, -PO 3 H 2, -OPO 3} H 2, -CONHSO 2 -, - SO 2 NHSO 2 -, - COCH 2 COCH 3 Is preferred. As the hydrophilic group, a sulfo group is preferable. The crosslinkable group is preferably a methacryl group or an allyl group. This polymer may have a crosslinkable group introduced by salt formation between the polar substituent of the polymer, a substituent having a counter charge and a compound having an ethylenically unsaturated bond, Other monomers, preferably hydrophilic monomers, may be further copolymerized.

Specifically, a silane coupling agent having an addition-polymerizable ethylenic double bond reactive group described in JP-A-10-282679 and an ethylenic compound described in JP-A-2-304441. The phosphorus compound which has a heavy bond reactive group is mentioned suitably. Crosslinkable group (preferably ethylenically unsaturated bond group) described in JP-A-2005-238816, JP-A-2005-12549, JP-A-2006-239867, JP-A-2006-215263, surface of support Those containing a low-molecular or high-molecular compound having a functional group that interacts with each other and a hydrophilic group are also preferably used.
More preferable are polymer polymers having an adsorbable group, a hydrophilic group, and a crosslinkable group that can be adsorbed on the support surface described in JP-A Nos. 2005-125749 and 2006-188038.

The content of unsaturated double bonds in the polymer resin for the undercoat layer is preferably 0.1 to 10.0 mmol, and most preferably 0.2 to 5.5 mmol per 1 g of the polymer.
The polymer for the undercoat layer preferably has a mass average molar mass of 5000 or more, more preferably 10,000 to 300,000.

  The undercoat layer of the present invention comprises, in addition to the above undercoat compound, a chelating agent, a secondary or tertiary amine, a polymerization inhibitor, an amino group, or a functional group having a polymerization inhibiting ability, in order to prevent contamination over time. Compounds having a group that interacts with the surface of an aluminum support (for example, 1,4-diazabicyclo [2,2,2] octane (DABCO), 2,3,5,6-tetrahydroxy-p-quinone, chloranil , Sulfophthalic acid, hydroxyethylethylenediaminetriacetic acid, dihydroxyethylethylenediaminediacetic acid, hydroxyethyliminodiacetic acid, and the like.

The undercoat layer is applied by a known method. The coating amount (solid content) of the undercoat layer is preferably from 0.1-100 mg / m ^2, and more preferably 1 to 30 mg / m ^2.

(Support)
As the support used in the lithographic printing plate precursor according to the invention, a known support is used. Of these, an aluminum plate that has been roughened and anodized by a known method is preferred.
In addition, the above aluminum plate is optionally subjected to micropore enlargement treatment or sealing treatment of an anodized film described in JP-A Nos. 2001-253181 and 2001-322365, and US Pat. 714,066, 3,181,461, 3,280,734 and 3,902,734, or alkali metal silicates as described in U.S. Pat. Surface hydrophilization treatment with polyvinylphosphonic acid or the like as described in each specification of 3,276,868, 4,153,461 and 4,689,272 is appropriately performed and performed. be able to.
The support preferably has a center line average roughness of 0.10 to 1.2 μm.

  If necessary, the support of the present invention includes an organic polymer compound described in JP-A-5-45885 and a silicon alkoxy compound described in JP-A-6-35174 on the back surface. A backcoat layer can be provided.

(Protective layer)
In the lithographic printing plate precursor according to the invention, a protective layer (overcoat layer) is preferably provided on the image recording layer. In addition to the function of suppressing the image formation inhibition reaction by blocking oxygen, the protective layer has a function of preventing scratches in the image recording layer and preventing ablation during high-illuminance laser exposure.

The protective layer having such characteristics is described in, for example, US Pat. No. 3,458,311 and Japanese Patent Publication No. 55-49729. As the low oxygen permeability polymer used for the protective layer, either a water-soluble polymer or a water-insoluble polymer can be appropriately selected and used, and two or more types can be mixed and used as necessary. it can. Specific examples include polyvinyl alcohol, modified polyvinyl alcohol, polyvinyl pyrrolidone, water-soluble cellulose derivatives, poly (meth) acrylonitrile, and the like.
As the modified polyvinyl alcohol, acid-modified polyvinyl alcohol having a carboxylic acid group or a sulfonic acid group is preferably used. Specifically, modified polyvinyl alcohols described in JP-A-2005-250216 and JP-A-2006-259137 are preferable.

Further, in order to enhance the oxygen barrier property, the protective layer preferably contains an inorganic layered compound such as natural mica and synthetic mica as described in JP-A-2005-119273.
Further, the protective layer may contain known additives such as a plasticizer for imparting flexibility, a surfactant for improving coating properties, and inorganic fine particles for controlling surface slipperiness. Further, the protective layer can contain the sensitizer described in the description of the image recording layer.

The protective layer is applied by a known method. The coating amount of the protective layer, the coating amount after drying is preferably in the range of 0.01 to 10 g / ^{m 2,} more preferably in the range of 0.02 to 3 g / ^{m 2,} and most preferably 0. in the range of 02~1g / ^{m 2.}

[Plate making method]
The plate making of the lithographic printing plate precursor according to the invention is preferably carried out by an on-press development method. The on-press development method includes an image exposure process for a lithographic printing plate precursor, a printing process in which an oil-based ink and an aqueous component are supplied and printed without performing any development process on the exposed lithographic printing plate precursor. And the unexposed portion of the lithographic printing plate precursor is removed during the printing process. Imagewise exposure may be performed on the printing machine after the lithographic printing plate precursor is mounted on the printing machine, or may be separately performed with a plate setter or the like. In the latter case, the exposed lithographic printing plate precursor is mounted on a printing machine without undergoing a development process. Thereafter, by using the printing machine and supplying the oil-based ink and the aqueous component and printing as it is, an on-press development process, that is, an image recording layer in an unexposed area is removed at an early stage of printing, Accordingly, the surface of the hydrophilic support is exposed to form a non-image part. As the oil-based ink and the aqueous component, ordinary lithographic printing ink and fountain solution are used.
This will be described in more detail below.

In the present invention, the light source used for image exposure is preferably a laser. Although the laser used for this invention is not specifically limited, The solid laser and semiconductor laser etc. which irradiate infrared rays with a wavelength of 760-1200 nm are mentioned suitably.
Regarding the infrared laser, the output is preferably 100 mW or more, the exposure time per pixel is preferably within 20 microseconds, and the irradiation energy amount is preferably 10 to 300 mJ / cm ² . In the laser, it is preferable to use a multi-beam laser device in order to shorten the exposure time.

  The exposed lithographic printing plate precursor is mounted on a plate cylinder of a printing press. In the case of a printing press equipped with a laser exposure device, image exposure is performed after a lithographic printing plate precursor is mounted on a plate cylinder of the printing press.

<Method of developing with a developer having a pH of 2 to 11>
In the normal development process using the alkali developer of (1), the protective layer is removed by the pre-water washing process, then the alkali development is performed, the alkali is washed and removed by the post-water washing process, the gum solution treatment is performed, and the drying is performed. When drying with the developer of pH 2-11 using the planographic printing plate precursor of the present invention, the protective layer and the image recording layer in the non-exposed area are removed all at once, and then immediately set in a printing machine. Can be printed. Such a developer having a pH of 2 to 11 can simultaneously perform development and gum solution treatment by containing a surfactant and / or a desensitizing water-soluble polymer in the developer, and after alkali development. The post-washing step that has been performed is not particularly required, and after the development and gum solution treatment with one solution, the drying step can be performed. Drying is preferably performed after the development and gum treatment, after removing excess developer using a squeeze roller. That is, a greatly simplified processing step (gum development) of development / gum processing-drying with a single solution becomes possible.
The development in the present invention is carried out according to a conventional method, such as a method in which a lithographic printing plate precursor subjected to image exposure at a liquid temperature of 0 to 60 ° C., preferably 15 to 40 ° C. is immersed in a developer and rubbed with a brush, or developed by spraying. This is done by spraying the liquid and rubbing with a brush.

  The pH 2 to 11 developer is preferably an aqueous solution containing water as a main component (containing 60% by mass or more of the developer mass), particularly a surfactant (anionic, nonionic, cationic, zwitterionic, etc.). ) And aqueous solutions containing water-soluble polymers are preferred. An aqueous solution containing both a surfactant and a water-soluble polymer is also preferred. The pH of the developer is more preferably 5 to 10.7, still more preferably 6 to 10.5, and most preferably 7.5 to 10.3.

  The anionic surfactant used in the developer is not particularly limited, but fatty acid salts, abietic acid salts, hydroxyalkane sulfonic acid salts, alkane sulfonic acid salts, dialkyl sulfosuccinic acid salts, linear alkyl benzene sulfonic acid salts, branched Chain alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl diphenyl ether (di) sulfonates, alkylphenoxy polyoxyethylene propyl sulfonates, polyoxyethylene alkyl sulfophenyl ether salts, sodium N-methyl-N-oleyl taurine N-alkylsulfosuccinic acid monoamide disodium salts, petroleum sulfonates, sulfated castor oil, sulfated beef tallow oil, sulfate esters of fatty acid alkyl esters, alkyl sulfate esters Tellurium salts, polyoxyethylene alkyl ether sulfates, fatty acid monoglyceride sulfates, polyoxyethylene alkylphenyl ether sulfates, polyoxyethylene styrylphenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates Salt, polyoxyethylene alkylphenyl ether phosphate ester salt, styrene-maleic anhydride copolymer partial saponification products, olefin-maleic anhydride copolymer partial saponification products, naphthalene sulfonate formalin condensates, etc. Can be mentioned. Among these, alkylbenzene sulfonates, alkyl naphthalene sulfonates, and alkyl diphenyl ether (di) sulfonates are particularly preferably used.

  Although it does not specifically limit as a cationic surfactant used for the said developing solution, A conventionally well-known thing can be used. Examples thereof include alkylamine salts, quaternary ammonium salts, alkyl imidazolinium salts, polyoxyethylene alkylamine salts, and polyethylene polyamine derivatives.

The nonionic surfactant used in the developer is not particularly limited, but is a polyethylene glycol type higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, alkyl naphthol ethylene oxide adduct, phenol ethylene oxide adduct, naphthol. Ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide ethylene oxide adduct, fat and oil ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, Dimethylsiloxane-ethylene oxide block copolymer, dimethylsiloxane- (propylene oxide-ethylene oxide ) Fatty acid ester of polyglycol type glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol and sorbitan, fatty acid ester of sucrose, alkyl ether of polyhydric alcohol, fatty acid amide of alkanolamines, etc. Can be mentioned. Among these, those having an aromatic ring and an ethylene oxide chain are preferable, and an alkyl-substituted or unsubstituted phenol ethylene oxide adduct or an alkyl-substituted or unsubstituted naphthol ethylene oxide adduct is more preferable.
The zwitterionic surfactant used in the developer is not particularly limited, and examples thereof include amine oxides such as alkyldimethylamine oxide, betaines such as alkylbetaines, and amino acids such as alkylamino fatty acid sodium. In particular, alkyldimethylamine oxide which may have a substituent, alkylcarboxybetaine which may have a substituent, and alkylsulfobetaine which may have a substituent are preferably used. Specific examples of these are described in paragraph numbers [0255] to [0278] of JP2008-203359, paragraph numbers [0028] to [0052] of JP2008-276166, and the like. More preferable specific examples include 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, alkyldiaminoethylglycine hydrochloride, lauryldimethylaminoacetic acid betaine, N-lauramidopropyldimethylbetaine, and N-lauric acid. And amidopropyldimethylamine oxide.

  Two or more surfactants may be used, and the ratio of the surfactant contained in the developer is preferably 0.01 to 20% by mass, more preferably 0.1 to 10% by mass.

  Examples of the water-soluble polymer used in the developer having a pH of 2 to 11 include soybean polysaccharide, modified starch, gum arabic, dextrin, fibrin derivatives (for example, carboxymethylcellulose, carboxyethylcellulose, methylcellulose, etc.) and modified products thereof, pullulan. , Polyvinyl alcohol and its derivatives, polyvinyl pyrrolidone, polyacrylamide and acrylamide copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer, styrene / maleic anhydride copolymer, etc. It is done.

  A well-known thing can be used for the said soybean polysaccharide, for example, there exists a brand name Soya Five (made by Fuji Oil Co., Ltd.) as a commercial item, and the thing of various grades can be used. What can be preferably used is one in which the viscosity of a 10% by mass aqueous solution is in the range of 10 to 100 mPa / sec.

  As the modified starch, known ones can be used, and starch such as corn, potato, tapioca, rice, and wheat is decomposed with acid or enzyme in the range of 5 to 30 glucose residues per molecule, and further in an alkali. It can be made by a method of adding oxypropylene or the like.

  Two or more water-soluble polymers can be used in combination. The content of the water-soluble polymer in the developer is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass.

The pH 2 to 11 developer used in the present invention may further contain a pH buffer.
Any pH buffering agent can be used without particular limitation as long as it exhibits a buffering effect at pH 2-11. In the present invention, weakly alkaline buffering agents are preferably used. For example, (a) carbonate ions and hydrogen carbonate ions, (b) borate ions, (c) water-soluble amine compounds and ions of the amine compounds, and their Combination use etc. are mentioned. That is, for example, (a) a combination of carbonate ion-bicarbonate ion, (b) borate ion, or (c) a combination of water-soluble amine compound-ion of the amine compound exhibits pH buffering action in the developer. Even when the developer is used for a long period of time, fluctuations in pH can be suppressed, and deterioration in developability due to fluctuations in pH, development of development residue, and the like can be suppressed. Particularly preferred is a combination of carbonate ions and bicarbonate ions.

  In order to allow carbonate ions and hydrogen carbonate ions to be present in the developer, carbonate and hydrogen carbonate may be added to the developer, or by adjusting the pH after adding carbonate or bicarbonate, Ions and bicarbonate ions may be generated. The carbonate and bicarbonate are not particularly limited, but are preferably alkali metal salts. Examples of the alkali metal include lithium, sodium, and potassium, and sodium is particularly preferable. These may be used alone or in combination of two or more.

  When (a) a combination of carbonate ions and bicarbonate ions is employed as the pH buffer, the total amount of carbonate ions and bicarbonate ions is preferably 0.05 to 5 mol / L relative to the total mass of the developer. 1-2 mol / L is more preferable, and 0.2-1 mol / L is particularly preferable.

The developer may contain an organic solvent. Examples of organic solvents that can be contained include aliphatic hydrocarbons (hexane, heptane, “Isopar E, H, G” (Esso Chemical Co., Ltd.)), aromatic hydrocarbons (toluene, xylene, etc.) Or halogenated hydrocarbons (methylene dichloride, ethylene dichloride, trichlene, monochlorobenzene, etc.) and polar solvents. Examples of polar solvents include alcohols (methanol, ethanol, propanol, isopropanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, 1-octanol, 2-octanol, 2-ethyl-1-hexanol, 1 -Nonanol, 1-decanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether, polyethylene glycol monomethyl Ether, polypropylene glycol, tetraethylene glycol, ethylene glycol monobutyl ether Ter, ethylene glycol monobenzyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, methylphenyl carbinol, n-amyl alcohol, methyl amyl alcohol, etc.), ketones (acetone, methyl ethyl ketone, ethyl butyl ketone, methyl isobutyl ketone) , Cyclohexanone, etc.), esters (ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, methyl lactate, butyl lactate, ethylene glycol monobutyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol acetate, diethyl phthalate, butyl levulinate Etc.), others (triethyl phosphate, tricresyl phosphate, N-phenylethanolamine) N- phenyldiethanolamine N- methyldiethanolamine, N- ethyldiethanolamine, 4- (2-hydroxyethyl) morpholine, N, N- dimethylacetamide, N- methylpyrrolidone and the like) and the like.
Two or more organic solvents can be used in combination in the developer.

  If the organic solvent is insoluble in water, it can be used after being solubilized in water using a surfactant or the like. If the developer contains an organic solvent, safety, ignition, From the viewpoint of property, the concentration of the solvent is preferably less than 40% by mass.

  In addition to the above, the developer having a pH of 2 to 11 may contain a preservative, a chelate compound, an antifoaming agent, an organic acid, an inorganic acid, an inorganic salt, and the like. Specifically, compounds described in paragraph numbers [0266] to [0270] of JP-A-2007-206217 can be preferably used.

  The developer can be used as a developer and a development replenisher for the exposed lithographic printing plate precursor, and is preferably applied to an automatic processor described later. When developing using an automatic processor, the developing solution becomes fatigued according to the amount of processing, and therefore the replenishing solution or fresh developing solution may be used to restore the processing capability.

  In the present invention, the development treatment with a developer having a pH of 2 to 11 can be suitably carried out by an automatic processor equipped with a developer supply means and a rubbing member. An automatic processor using a rotating brush roll as the rubbing member is particularly preferable. Further, the automatic processor is preferably provided with a means for removing excess developer such as a squeeze roller and a drying means such as a hot air device after the development processing means.

<On-machine development processing>
When printing is performed by supplying dampening water and printing ink to the lithographic printing plate precursor exposed imagewise, the image recording layer cured by exposure has a printing ink acceptance having an oleophilic surface in the exposed portion of the image recording layer. Forming part. On the other hand, in the unexposed area, the uncured image recording layer is removed by dissolution or dispersion by the supplied dampening water and / or printing ink, and a hydrophilic surface is exposed in that area. As a result, the fountain solution adheres to the exposed hydrophilic surface, and the printing ink is deposited on the image recording layer in the exposed area and printing is started.

Here, dampening water or printing ink may be supplied to the printing plate first, but printing is first performed in order to prevent the dampening water from being contaminated by the removed image recording layer components. It is preferable to supply ink.
In this way, the lithographic printing plate precursor according to the invention is developed on the machine on an offset printing machine and used as it is for printing a large number of sheets.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. In the polymer compound, the molecular weight is a mass average molar mass (Mw), and the ratio of repeating units is a mole percentage, except for those specifically defined.

[Synthesis Example of Branched Polymer Compound of the Present Invention]
The multi-branched polymer used in the present invention has a large number of functional groups that can react with specific functional groups after radical polymerization using a polymerization initiator and / or chain transfer agent containing specific functional groups in the molecule. It can be synthesized by a known polymerization method such as a method of condensing with a polyfunctional compound and a method of radical polymerization using a polyfunctional chain transfer agent. A radical polymerization method is particularly preferred. The synthesis example of the hyperbranched polymer used for this invention is described below.

[Synthesis of Polymer Compound (A-1)]
1-methoxy-2-propanol heated to 70 ° C. under nitrogen flow: 40.19 g; methoxypolyethylene glycol methacrylate (Blenmer PME-100 manufactured by NOF Corporation, ethylene oxide repeat number 2): 75.29 g, methyl Methacrylate: 50.06 g, methacrylic acid: 8.61 g, tris (2-mercaptopropionyloxyethyl) isocyanurate: 1.752 g, polymerization initiator V-601 (dimethyl-2,2 ′ manufactured by Wako Pure Chemical Industries, Ltd.) —Azobis (2-methylpropionate)): 1.151 g, 1-methoxy-2-propanol: 160.75 g of a mixed solution was added dropwise over 2 hours and 30 minutes. V-601: 0.115g was further added after completion | finish of dripping, and it heated up at 90 degreeC, and continued reaction for 2 hours. After the reaction, the reaction solution was cooled to 50 ° C. and 1-methoxy-2-propanol: 117.51 g was added to dilute the reaction solution. To the resulting reaction mixture, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxide free radical: 0.783 g, glycidyl methacrylate: 15.66 g and 1-methoxy-2-propanol: 10. A mixing solution consisting of 97 g was added and stirred for 5 minutes. The reaction mixture was heated to 90 ° C. and stirred for 10 minutes, then 1.79 g of tetraethylammonium bromide was added, and tetraethylammonium bromide adhering to the reaction vessel wall was washed away with 1-methoxy-2-propanol: 24.58 g. It was. After stirring at 90 ° C. for 18 hours, 239.6 g of 1-methoxy-2-propanol was added to dilute the reaction mixture. The Mw measured by GPC of the polymer compound (A-1) solution represented by the above structural formula thus obtained was 44,000, and the solid content concentration was 24.5% by mass.

[Synthesis of Polymer Compound (A-2)]
1-methoxy-2-propanol heated to 70 ° C. under nitrogen flow: 40.61 g, Bremer PME-100: 75.29 g, methyl methacrylate: 60.07 g, tris (2-mercaptopropionyloxyethyl) isocyanurate: A mixed solution consisting of 1.75 g, V-601 (manufactured by Wako Pure Chemical Industries, Ltd.): 1.15 g and 1-methoxy-2-propanol: 162.43 g was added dropwise over 2 hours and 30 minutes. After completion of the dropwise addition, the reaction was continued for another 3 hours. After the reaction, a solid was precipitated when poured into 4000 g of well stirred water. The precipitated solid was filtered, washed with water and dried under reduced pressure to obtain a polymer compound (A-2) represented by the above structural formula. Mw of the obtained polymer was 50,000.

[Examples 1-2, Comparative Examples 1-2]

[Production of cured films (1) to (2)]
<Coating liquid (1) (2)>
On the polyethylene terephthalate (PET) film, the coating liquids (1) and (2) having the following composition were bar-coated and then oven-dried at 100 ° C. for 60 seconds to form a film having a dry coating amount of 1.0 g / m ² . . Then, UV light was irradiated and the cured film (1) and (2) was obtained.

<Coating liquid (1)>
・ Polymer compound (A-1)
(Adjusted to a solid content concentration of 10% with a mixed solvent of 1-methoxy-2-propanol / 2-butanone (1/1)) 2.4 g
Infrared absorbing dye (1) [the following structure] 0.030 g
・ Polymerization initiator (1) [the following structure] 0.162 g
Polymerizable compound tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
-Mixed solvent of 1-methoxy-2-propanol / 2-butanone (1/1) 0.17 g

<Coating liquid (2)>
A cured film was produced in the same manner as the cured film (1) except that the polymer compound (A-1) was changed to (A-2). The obtained cured film (2) had a dry coating amount of 1.0 g / m ² .

<Coating liquids (3), (4)>
A cured film was produced in the same manner as the cured film (1) except that the polymer compound (A-1) was changed to the following linear polymer R-1 or multibranched polymer R-2, respectively.

[Evaluation of cured film (durability evaluation of film)]
In order to measure the durability of the film formed on PET, the obtained film surface was rubbed 100 times with a nonwoven fabric (BEMCOT, manufactured by Asahi Chemical Fiber Co., Ltd.), and the surfaces of the members before and after that were observed. The pressure at the time of rubbing when the film was peeled off or scratches that could be visually confirmed was measured. The results are shown in Table 4.

[Examples 3-11, 13, 14 and Comparative Examples 3-6]

[Preparation of lithographic printing plate precursors (1) to (7)]
(1) Production of support (1)
In order to remove rolling oil on the surface of an aluminum plate (material JIS A 1050) having a thickness of 0.3 mm, a degreasing treatment was performed at 50 ° C. for 30 seconds using a 10 mass% sodium aluminate aqueous solution, and then the hair diameter was adjusted to 0. The aluminum surface was grained using ^three 3 mm bundled nylon brushes and a pumice-water suspension (specific gravity 1.1 g / cm ³ ) having a median diameter of 25 μm and washed well with water. This plate was etched by being immersed in a 25 mass% aqueous sodium hydroxide solution at 45 ° C for 9 seconds, washed with water, further immersed in a 20 mass% nitric acid aqueous solution at 60 ° C for 20 seconds, and washed with water. At this time, the etching amount of the grained surface was about 3 g / m ² .

Next, an electrochemical roughening treatment was performed continuously using an alternating voltage of 60 Hz. The electrolytic solution at this time was a 1% by mass nitric acid aqueous solution (containing 0.5% by mass of aluminum ions) and a liquid temperature of 50 ° C. The AC power source waveform is electrochemical roughening treatment using a trapezoidal rectangular wave alternating current with a time ratio TP of 0.8 msec until the current value reaches a peak from zero, a duty ratio of 1: 1, and a trapezoidal rectangular wave alternating current. Went. Ferrite was used for the auxiliary anode. The current density was 30 A / dm ² at the peak current value, and 5% of the current flowing from the power source was shunted to the auxiliary anode. The amount of electricity in nitric acid electrolysis was 175 C / dm ² when the aluminum plate was the anode. Then, water washing by spraying was performed.

Subsequently, nitric acid electrolysis was performed with an aqueous solution of 0.5% by mass of hydrochloric acid (containing 0.5% by mass of aluminum ions) and an electrolytic solution having a liquid temperature of 50 ° C. under the condition of an electric quantity of 50 C / dm ² when the aluminum plate was the anode. In the same manner as above, an electrochemical surface roughening treatment was performed, followed by washing with water by spraying.
Next, a 2.5 g / m ² direct current anodic oxide film having a current density of 15 A / dm ² was provided on the plate as a 15% by weight sulfuric acid aqueous solution (containing 0.5% by weight of aluminum ions) as an electrolyte, followed by washing with water. And dried to prepare a support (1).
Thereafter, in order to ensure the hydrophilicity of the non-image area, the support (1) was subjected to a silicate treatment at 60 ° C. for 10 seconds using an aqueous 2.5 mass% No. 3 sodium silicate solution, and then washed with water for support. Body (2) was obtained. The adhesion amount of Si was 10 mg / m ² . The centerline average roughness (Ra) of this substrate was measured using a needle having a diameter of 2 μm and found to be 0.51 μm.

(2) Formation of undercoat layer Next, the following undercoat layer coating solution (1) is applied onto the support (2) so that the dry coating amount is 20 mg / m ² , and used in the following experiments. A support having a layer was prepared.

<Coating liquid for undercoat layer (1)>
-Undercoat layer compound (1) having the following structure: 0.18 g
・ Hydroxyethyliminodiacetic acid 0.10g
・ Methanol 55.24g
・ Water 6.15g

(3) Formation of image recording layer The image recording layer coating solution (1) having the following composition was bar-coated on the undercoat layer formed as described above, and then oven-dried at 100 ° C for 60 seconds to obtain a dry coating amount. An image recording layer of 1.0 g / m ² was formed.
The image recording layer coating solution (1) was obtained by mixing and stirring the following photosensitive solution (1) and microgel solution (1) immediately before coating.

<Photosensitive solution (1)>
-Polymer compound represented by the general formula (1) (described in Table 5) 2.4 g
Infrared absorbing dye (1) [above structure] 0.030 g
-Polymerization initiator (1) [The above structure] 0.162 g
Polymerizable compound tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 0.192 g
・ Low molecular weight hydrophilic compound Tris (2-hydroxyethyl) isocyanurate 0.062g
・ Low molecular weight hydrophilic compound (1) [the following structure] 0.050 g
-Sensitizing agent Phosphonium compound (1) [the following structure] 0.055 g
・ Sensitizer Benzyl-dimethyl-octylammonium ・ PF ₆ salt 0.018g
-Sensitizing agent Ammonium group-containing polymer [the following structure, reduced specific viscosity 44 cSt / g / ml] 0.035 g
・ Fluorosurfactant (1) [The following structure] 0.008g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

<Microgel solution (1)>
・ Microgel (1) 2.640 g
・ Distilled water 2.425g

  The structures of the phosphonium compound (1), the low molecular weight hydrophilic compound (1), the ammonium group-containing polymer, and the fluorosurfactant (1) are as shown below.

-Synthesis of microgel (1)-
As an oil phase component, trimethylolpropane and xylene diisocyanate adduct (Mitsui Chemical Polyurethane Co., Ltd., Takenate D-110N) 10 g, pentaerythritol triacrylate (Nippon Kayaku Co., Ltd., SR444) 3.15 g, And 0.1 g of Pionein A-41C (manufactured by Takemoto Yushi Co., Ltd.) was dissolved in 17 g of ethyl acetate. As an aqueous phase component, 40 g of a 4% by mass aqueous solution of polyvinyl alcohol (PVA-205 manufactured by Kuraray Co., Ltd.) was prepared. The oil phase component and the aqueous phase component were mixed and emulsified for 10 minutes at 12,000 rpm using a homogenizer. The obtained emulsion was added to 25 g of distilled water, stirred at room temperature for 30 minutes, and then stirred at 50 ° C. for 3 hours. The microgel solution thus obtained was diluted with distilled water to a solid content concentration of 15% by mass, and this was designated as the microgel (1). When the average particle size of the microgel was measured by a light scattering method, the average particle size was 0.2 μm.

(3) Formation of Protective Layer After the protective layer coating solution (1) having the following composition was further bar-coated on the image recording layer, it was oven-dried at 120 ° C. for 60 seconds, and the dry coating amount was 0.15 g / m ^2. The lithographic printing plate precursors (1) to (7) [Examples 3 to 9] were obtained.

<Protective layer coating solution (1)>
・ Inorganic layered compound dispersion (1) 1.5 g
-Polyvinyl alcohol (Nippon Synthetic Chemical Industry Co., Ltd. CKS50, sulfonic acid modification,
Saponification degree 99 mol% or more, polymerization degree 300) 6% by mass aqueous solution 0.55 g
・ Polyvinyl alcohol (PVA-405 manufactured by Kuraray Co., Ltd.)
Degree of saponification 81.5 mol%, degree of polymerization 500) 6% by weight aqueous solution 0.03 g
・ Nippon Emulsion Co., Ltd. surfactant (Emalex 710) 1% by weight aqueous solution 0.86g
・ Ion-exchanged water 6.0g

(Preparation of inorganic layered compound dispersion (1))
6.4 g of synthetic mica Somasif ME-100 (manufactured by Coop Chemical Co., Ltd.) was added to 193.6 g of ion-exchanged water, and dispersed using an homogenizer until the average particle size (laser scattering method) became 3 μm. The aspect ratio of the obtained dispersed particles was 100 or more.

[Preparation of lithographic printing plate precursor (8)]
A lithographic printing plate precursor (8) [for Comparative Example 3] is prepared in the same manner as the lithographic printing plate precursor (1) except that the polymer compound (A-1) is changed to the linear polymer (R-1). did. The image recording layer of the resulting lithographic printing plate precursor (8) had a dry coating amount of 1.0 g / m ² .

[Preparation of lithographic printing plate precursors (9) to (11)]
The lithographic printing plate precursor (9) is the same as the lithographic printing plate precursor (1) except that the polymer compound (A-1) is changed to the multi-branched polymers (R-2) to (R-4) shown below. To (11) [for Comparative Examples 4 to 6] were produced. The image recording layers of the resulting lithographic printing plate precursors (9) to (11) had a dry coating amount of 1.0 g / m ² .

[Preparation of lithographic printing plate precursor (12)]
An image recording layer coating liquid (2) having the following composition is bar-coated on the above support having an undercoat layer, followed by oven drying at 100 ° C. for 60 seconds to form an image recording layer having a dry coating amount of 1.0 g / m ^2. Then, the protective layer coating solution (1) is further bar-coated on the image recording layer, followed by oven drying at 120 ° C. for 60 seconds to form a protective layer having a dry coating amount of 0.15 g / m ^2. A lithographic printing plate precursor (12) [for Example 10] was obtained.
The image recording layer coating solution (2) was obtained by mixing and stirring the following photosensitive solution (2) and microgel solution (1) immediately before coating.

<Photosensitive solution (2)>
-Polymer compound represented by the general formula (1) (described in Table 5) 2.4 g
Infrared absorbing dye (1) [above structure] 0.030 g
・ Polymerization initiator (1) [above structure] 0.162 g
Polymerizable compound (1) [the following structure] 0.192 g
・ Low molecular weight hydrophilic compound Tris (2-hydroxyethyl) isocyanurate 0.062g
・ Low molecular weight hydrophilic compound (1) [above structure] 0.050 g
・ Grease sensitizer Phosphonium compound (1) [above structure] 0.055 g
・ Sensitizer Benzyl-dimethyl-octylammonium ・ PF ₆ salt 0.018g
-Sensitizer Ammonium group-containing polymer [The above structure, reduced specific viscosity 44 cSt / g / ml] 0.035 g
・ Fluorine-based surfactant (1) [above structure] 0.008 g
・ 2-butanone 1.091g
・ 1-methoxy-2-propanol 8.609g

<Microgel solution (1)>
・ Microgel (1) 2.640 g
・ Distilled water 2.425g

  The structure of the polymerizable compound is as shown below.

[Preparation of lithographic printing plate precursor (13)]
The following image recording layer coating solution (3) is bar-coated on the above support having an undercoat layer, followed by oven drying at 70 ° C. for 60 seconds to form an image recording layer having a dry coating amount of 0.6 g / m ^2. The lithographic printing plate precursor (13) [for Example 11] was obtained.

<Image recording layer coating solution (3)>
-Polymer fine particle aqueous dispersion (1) 20.0 g
・ Infrared absorbing dye (2) [The following structure] 0.2g
・ Polymerization initiator Irgacure250 (Ciba Specialty Chemicals) 0.5g
-Polymerizable compound SR-399 (Sartomer) 1.50 g
・ Mercapto-3-triazole 0.2g
-Polymer compound represented by the general formula (1) (described in Table 5) 4.5 g
・ N-propanol 55.0g
・ 2-butanone 17.0g

In addition, the compounds described by trade names in the above composition are as follows.
IRGACURE 250: (4-methoxyphenyl) [4- (2-methylpropyl) phenyl] iodonium = hexafluorophosphate (75% by mass propylene carbonate solution)
・ SR-399: Dipentaerythritol pentaacrylate

(Production of polymer fine particle aqueous dispersion (1))
A 1000 ml four-necked flask was equipped with a stirrer, thermometer, dropping funnel, nitrogen inlet tube, reflux condenser, and nitrogen gas was introduced to perform deoxygenation, while polyethylene glycol methyl ether methacrylate (average of PEGMA ethylene glycol) The repeating unit was 50) 10 g, distilled water 200 g and n-propanol 200 g were added and heated until the internal temperature reached 70 ° C. Next, a premixed mixture of 10 g of styrene (St), 80 g of acrylonitrile (AN) and 0.8 g of 2,2′-azobisisobutyronitrile was added dropwise over 1 hour. After completion of the dropwise addition, the reaction was continued for 5 hours, and then 0.4 g of 2,2′-azobisisobutyronitrile was added to raise the internal temperature to 80 ° C. Subsequently, 0.5 g of 2,2′-azobisisobutyronitrile was added over 6 hours. Polymerization progressed 98% or more at the stage of reaction for a total of 20 hours, and a polymer fine particle aqueous dispersion (1) having a mass ratio of PEGMA / St / AN = 10/10/80 was obtained. The particle size distribution of the polymer fine particles had a maximum value at a particle size of 150 nm.

  Here, the particle size distribution is obtained by taking an electron micrograph of polymer fine particles, measuring a total of 5000 fine particle sizes on the photograph, and a logarithmic scale between 0 and the maximum value of the obtained particle size measurement values. And the frequency of appearance of each particle size was plotted and obtained. For non-spherical particles, the particle size of spherical particles having the same particle area as that on the photograph was used as the particle size.

[Preparation of lithographic printing plate precursors (15) and (16)]
In the lithographic printing plate precursor (15), the polymerizable compound [Tris (acryloyloxyethyl) isocyanurate] in the photosensitive solution (1) is replaced with the exemplified compound M-16 in this specification, and in the lithographic printing plate precursor (16) The lithographic printing plate precursor (15) [for Example 13] and the lithographic printing plate precursor (16) [16] were prepared in the same manner as in the production of the lithographic printing plate precursor (1) except that it was replaced with the exemplified compound M-20 in the specification. For Example 14] was prepared.

[Evaluation of planographic printing plate precursor]
(1) On-machine developability The obtained lithographic printing plate precursor was subjected to the conditions of an external drum rotation speed of 1000 rpm, a laser output of 70%, and a resolution of 2400 dpi on a Fujifilm Corp. Luxel PLANETTER T-6000III equipped with an infrared semiconductor laser. Exposed. The exposure image included a solid image and a 50% halftone dot chart of a 20 μm dot FM screen.
The obtained exposed original plate was attached to a plate cylinder of a printing machine LITHRONE 26 manufactured by Komori Corporation without developing. Equality-2 (manufactured by FUJIFILM Corporation) / tap water = 2/98 (volume ratio) dampening water and Values-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) After dampening water and ink were supplied by the standard automatic printing start method of LITHRONE 26 and developed on the machine, 100 sheets were printed on Tokuhishi Art (76.5 kg) paper at a printing speed of 10,000 sheets per hour.
The number of print sheets required until the on-press development on the printing press of the unexposed portion of the image recording layer was completed and the ink was not transferred to the non-image portion was measured as on-press developability. The results are shown in Table 5.

(2) Printing durability After the above-described evaluation of on-press developability, the printing was further continued. As the number of printed sheets was increased, the image recording layer was gradually worn out, so that the ink density on the printed material decreased. Printing durability was evaluated using the number of printed copies when the value measured by the Gretag densitometer for the 50% halftone dot area ratio of the FM screen in the printed material was 5% lower than the measured value for the 100th printed sheet. . The results are shown in Table 5.

  As is apparent from Table 5, in the examples using the branched polymer having an isocyanuric acid skeleton of the present invention, compared to the comparative example using a linear polymer and a branched polymer having no isocyanuric acid skeleton. Developability and printing durability are improved. Further, developability and printing durability are further improved by the combination of the branched polymer having an isocyanuric acid skeleton of the present invention and the polymerizable compound having an isocyanuric acid skeleton.

[Examples 15 to 16 and Comparative Examples 7 to 8]

[Preparation of lithographic printing plate precursor (17)]
<Production of support>
An aluminum plate having a thickness of 0.3 mm was etched by being immersed in a 10% by mass aqueous sodium hydroxide solution at 60 ° C. for 25 seconds, washed with running water, neutralized with a 20% by mass nitric acid aqueous solution, and then washed with water. This was subjected to an electrolytic surface roughening treatment in a 1% by mass nitric acid aqueous solution using an alternating waveform current of a sine wave at an anode time electricity of 300 coulomb / dm ² . Subsequently, after dipping in a 1% by mass aqueous sodium hydroxide solution at 40 ° C. for 5 seconds and then in a 30% by mass sulfuric acid aqueous solution and desmutting at 60 ° C. for 40 seconds, the current density in a 20% by mass sulfuric acid aqueous solution was 2A / Anodization was performed for 2 minutes so that the thickness of the anodized film was 2.7 g / m ² under the condition of dm ² . When the surface roughness was measured, it was 0.28 μm (Ra display according to JIS B0601). The support thus obtained is referred to as support A.

<Preparation of support B>
The support A was immersed for 10 seconds in a processing solution at 53 ° C. in which 0.4% by mass of polyvinylphosphonic acid (PCAS) was dissolved in pure water, and the excess processing solution was removed with a nip roll. After that, it was washed with 60 ° C. well water containing 100 ppm of calcium ion for 4 seconds, further washed with 25 ° C. pure water for 4 seconds, and excess pure water was removed with a nip roll. In the subsequent drying step, moisture on the aluminum plate was completely removed, and a support B was produced.

An image recording layer coating solution (5) having the following composition was applied onto the support B so that the dry coating mass was 1.4 g / m ² and dried at 100 ° C. for 1 minute to form an image recording layer. . [For Example 15]

<Image recording layer coating solution (5)>
Polymerizable compound Tris (acryloyloxyethyl) isocyanurate (NK ester A-9300, manufactured by Shin-Nakamura Chemical Co., Ltd.) 3.33 parts by mass Polymer compound (A-1) (Mw: 44,000) 26.7 parts by mass Parts Sensitizing dye (D-1) 0.32 parts by weight Polymerization initiator (I-1) 0.61 parts by weight Chain transfer agent (S-2) 0.57 parts by weight N-nitrosophenylhydroxylamine aluminum salt 0. 020 parts by mass ε-phthalocyanine pigment dispersion 0.71 parts by mass [Pigment: 15% by mass, allyl methacrylate / methacrylic acid (molar ratio 80/20) copolymer as dispersing agent (Mw: 60,000): 10 masses] %,
As a solvent, cyclohexanone / methoxypropyl acetate / 1-methoxy-2-propanol = 15% by mass / 20% by mass / 40% by mass]
Fluorine-based nonionic surfactant (Megafac F780F,
Dainippon Ink & Chemicals, Inc.) 0.016 parts by mass 2-butanone 47 parts by mass propylene glycol monomethyl ether 45 parts by mass

On the image recording layer, a protective layer coating solution (2) having the following composition was applied using a bar so that the dry coating amount was 0.50 g / m ^2, and then dried at 125 ° C. for 70 seconds for protection. A layer was formed to prepare a lithographic printing plate precursor (17).

<Protective layer coating solution (2)>
・ 0.6 g of the following mica dispersion
・ Sulphonic acid-modified polyvinyl alcohol 0.8g
(Goselan CKS-50, manufactured by Nippon Synthetic Chemical Co., Ltd. (degree of saponification: 99 mol%,
Average polymerization degree: 300, modification degree: about 0.4 mol%))
・ Surfactant (Emalex 710, manufactured by Nippon Emulsion Co., Ltd.) 0.002g
・ Water 13g

(Preparation of mica dispersion)
To 368 g of water, 32 g of synthetic mica (Somasif ME-100, manufactured by Co-op Chemical Co., Ltd., aspect ratio: 1000 or more) is added, and dispersed using an homogenizer until the average particle size (laser scattering method) becomes 0.5 μm. A liquid was obtained.

[Preparation of lithographic printing plate precursors (18) and (19)]
The lithographic printing plate precursors (18) and (19) [for Comparative Examples 7 and 8] were used in the same manner as the lithographic printing plate precursor (17) except that the polymer compound A-1 was changed to R-1 or R-2. Produced.

[Preparation of lithographic printing plate precursor (20)]
The lithographic printing plate precursor (20) is the same as the lithographic printing plate precursor (17) except that the polymerizable compound tris (acryloyloxyethyl) isocyanurate in the image recording layer coating solution (5) is changed to the polymerizable compound (1). ) [For Example 16] was prepared.

(1) Exposure, development and printing The above lithographic printing plate precursors are converted into FUJIFILM Electronic Imaging.
Ltd .. Image exposure was performed with a Violet semiconductor laser plate setter Vx9600 (equipped with an InGaN-based semiconductor laser (emission wavelength 405 nm ± 10 nm / output 30 mW)) manufactured by (FFEI). Image drawing was performed at a resolution of 2,438 dpi, using an FM screen (TAFFETA 20) manufactured by Fuji Film Co., Ltd., with a plate surface exposure of 0.05 mJ / cm ² so that the dot area ratio was 50%.
Next, after preheating at 100 ° C. for 30 seconds, development processing was performed with an automatic developing processor having a structure as shown in FIG.
Here, the automatic development processor includes a developing unit 6 that develops a planographic printing plate precursor (hereinafter referred to as “PS plate”) 4 and a drying unit 10 that dries the developed PS plate 4. An insertion port is formed in the side plate of the automatic processor (the left portion in FIG. 1), and the PS plate 4 inserted from the insertion port is loaded by a carry-in roller 16 provided on the inner surface of the side plate of the automatic processor. It is conveyed to the developing unit 6. In the developing tank 20 of the developing unit 6, a conveyance roller 22, a brush roller 24, and a squeeze roller 26 are sequentially provided from the upstream side in the conveyance direction, and a backup roller 28 is provided at an appropriate position therebetween. The PS plate 4 is developed by being immersed in the developer while being conveyed by the conveying roller 22 and rotating the brush roller 24 to remove the protective layer and the image recording layer unexposed portion of the PS plate 4. The developed PS plate 4 is conveyed to the next drying unit 10 by a squeeze roller (unloading roller) 26.
The drying unit 10 is provided with a guide roller 36 and a pair of skewer rollers 38 in order from the upstream side in the transport direction. The drying unit 10 is provided with drying means such as hot air supply means and heat generation means (not shown). The drying unit 10 is provided with a discharge port, and the PS plate 4 dried by the drying means is discharged, and the automatic development processing for the PS plate is completed. The automatic processor used in the examples has one brush roller having an outer diameter of 50 mm in which fibers made of polybutylene terephthalate (hair diameter: 200 μm, hair length: 17 mm) are implanted in the same direction as the conveying direction. 200 revolutions per minute (peripheral speed of the brush tip: 0.52 m / sec). The temperature of the developer was 30 ° C. The planographic printing plate precursor was transported at a transport speed of 82 cm / min (the transport speed was changed when developing properties were evaluated). After the development processing, drying was performed in a drying section. The drying temperature was 80 ° C.

  Next, the lithographic printing plate was attached to a printing machine SOR-M manufactured by Heidelberg, and dampening water (EU-3 (Etchi solution manufactured by FUJIFILM Corporation) / water / isopropyl alcohol = 1/89/10 (volume ratio)). And TRANS-G (N) black ink (manufactured by Dainippon Ink & Chemicals, Inc.) was used to print on high-quality paper “Shiraoi” (manufactured by Nippon Paper Industries Co., Ltd.) at a printing speed of 6000 sheets per hour.

(Developer)
Table 6 below shows the composition of the developer 1 used in Examples and Comparative Examples. The following New Coal B13 (manufactured by Nippon Emulsifier Co., Ltd.) is polyoxyethylene β-naphthyl ether (oxyethylene average number n = 13), and gum arabic has a mass average molar mass (Mw) of 20 Ten thousand things were used.

(2) Evaluation The printing durability and developability were evaluated as follows. The results are shown in Table 7.

<Developability>
Development was performed at various conveying speeds, and the cyan density of the non-image area was measured with a Macbeth densitometer (manufactured by Gretag Macbeth). The conveyance speed at which the cyan density of the non-image area is equal to the cyan density of the aluminum substrate is obtained, and the leading edge of the original is immersed in the developer at this conveying speed, and then the leading edge of the original comes out of the developing liquid. The development time was defined as the development time.

<Print durability>
Printing was performed after evaluating the developability described above. As the number of printed sheets was increased, the image recording layer was gradually worn out, so that the ink density on the printed material decreased. Printing durability was evaluated using the number of printed copies when the value measured by the Gretag densitometer for the 50% halftone dot area ratio of the FM screen in the printed material was 5% lower than the measured value for the 100th printed sheet. . The results are shown in Table 7.

  As is clear from Table 7, in the examples using the branched polymer having an isocyanuric acid skeleton of the present invention, compared to the comparative example using a linear polymer and a branched polymer having no isocyanuric acid skeleton. Developability and printing durability are improved. Further, developability and printing durability are further improved by the combination of the branched polymer having an isocyanuric acid skeleton of the present invention and the polymerizable compound having an isocyanuric acid skeleton.

4 Planographic printing plate precursor (PS version)
6 Developing Unit 10 Drying Unit 16 Loading Roller 20 Developing Tank 22 Transporting Roller 24 Brush Roller 26 Squeeze Roller (Unloading Roller)
28 Backup roller 36 Guide roller 38 Skewer roller

Claims (5)

A lithographic printing plate precursor having an image recording layer containing a polymerizable composition on a support,
The polymerizable composition contains a polymerizable compound, a polymerization initiator, and a polymer compound ,
The polymer compound, isocyanuric acid skeleton and stagnation, the lithographic printing plate precursor, characterized in der Rukoto polymer compound polymer chain is branched. The lithographic printing plate precursor as claimed in claim 1, wherein the polymer chain contains a repeating unit having an ethylenically unsaturated group. The lithographic printing plate precursor as claimed in claim 1 or 2, wherein the polymerizable compound has an isocyanuric acid skeleton. The lithographic printing plate precursor as claimed in any one of claims 1 to 3, wherein the image recording layer is removable with at least one of printing ink and fountain solution. The lithographic printing plate precursor according to claim 4 is mounted on a printing press and imagewise exposed with a laser or imagewise exposed with a laser and then mounted on a printing press to form a lithographic printing plate precursor. A lithographic printing method in which at least one of printing ink and fountain solution is supplied to remove an unexposed portion of the image recording layer and print.

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